Variabilitycf Precipiturion
PscificNotrhwest:S pufinf
Temporol C horocteristics
DqnielM. Johnsonsnd Jshn O. Faff
Departmentof G e o g r o p h y
PortlondStoteUniversity
Po,rtlsftdo
Oregon 197201
Moy, 1982
W a t e r R e s o u r c eR
sesearch
Institute
O r e g o nS t a t e U n i v e r s i t y
C o r v a l l i s ,O r e g o n
VARIABILITY OF PRECIPITATION IN THE PACIFIC NORTHWEST:
SPATIAL AND TEMPORAL CIIARACTERISTICS
by
Dani.el M. Johnson and John O. Dart
Department of Geography, portland State University
PortJ_and, Oregon gTZOI
Conpletion
Projeer
Report for
A-050-ORE
Office
of Water Research and Technology
United
States Department of the Interior
Project
Sponsored by:
Water Resources Research Institute
oregon state
Corvallis,
university
Oregon 9733L
The work upon whi-eh thls publication
is based was supported in part by funds
provided by the Office of l,Iater Research and Technofoiy (project
No. A-050-ORE),
U.S. Department of the Interior,
Washington, D.C., as authorized by the Water
Research and Development Act of 197g, p:L. 95_467.
Contents of this publication
do not necessarily
reflect
the views and polices
of the office of water Research and Technologyr'u.s.
Department of the rnterior
nor does mention of trade names or commercial products constitute
their
endorsement or reconrmendation for use by the U.S. Government.
I^IRRI-77
May 1-982
ABSTRACT
A detaired
study of spatial
and temporal
aspects of
precipi-tation
in the pacific
Northwest reveals
much about
the natural
variabirity
of this important climatic
erement.
The data base consists
of monthiy,
seasonal
a
n
d
annual
(water year) totars
o f p r e c i p -i t a t i 6 n
for a network of 244
climatological
stations
in
Oregon,
Washington
and the
adjacent
are3.
A
complete
set- of
deslriptive
and
inferential
statistics
was carcurated
and is presented in
tabular
form.
Maps
of
key
statistics
means,
coefficients
of
vafiation
and interstation
correlation
-coefficients
depict
spatial
patterns.
The 4T_year
normal period _ is shown to re suffi-cient
for the making of
probability
estimates of seasonal and annual precipitation.
Temporar
.orecipitation
variabirity
over the rast
in
seasonar
and
annuar
raa years is studied with 7g
)n and Washington.
Tren<ls,
letermined
and strow that
the
. changes is great.
There is
:her a progressive
increase or
:ion in Oregon over the Iast
re has been a tendency
for
shorrer time periods are .r,.rnff""ut";:tht"i;
#ffff:,
":;:
being
a 9-term
weighted
moving'."-r.g"
used to filter
out
short-term
os_cillations
drrd
r
the
other
being
the
carculation
of
decadar
varues
of
means
and
standard
deviations
The one persistent
temporar
pattern
throughout
the region
is a downwlrd
trend
extending
from the
Lggas to
:ecovery
in
recent
decades.
variations
of this
pattern.
s marked
by
extremely
high
:ding
consistent
wi+-h studies
iii
FOREWORD
The Water Resources Research Inst,i-tute,
University
\irater resources
aspects of the quali.ty
use.
The Institute
and quantity
programs of multidisciplinary
The rnstitute
Provides
state
on natters
and regional
statewide
land resources.
a necessary conrmunications and coordination
state,
and federal
link
as welL as
governnent'
conrmunity at universities
also
The Institute
research.
of water-related
program of graduate education
the inter-disciplinary
involving
beneficial
for
in hrater and related
and the broad research
sector,
fosters,
and education
of water available
research
between the agencies of local,
the private
research
and coordinates
administers
on the Oregon State
The Institute
Campus, serves the State of Oregon.
encourages and facilitates
all
located
in the
eoordinates
resources
in water
at
Oregon State University.
It
is
policy
Institute
water-rel-ated
research
The Institute
neither
It
such research.
facts
to make available
of significant
the results
and colleges-
conducted in Oregonts universities
endorses nor rejects
the findings
does recorrmend carefuL
consideration
by those concerned with
the solution
of the authors
of
of the accumulated
of water-related
problems.
ACKNOWLEDGn{ENTS
Several
made important
individuals
the completion
thanks go to Karen King,
processing
cartography
and edited
report.
of the final
the entire
The authors
and particuLarly
report.
1V
to all.
are grateful
valued
to Cheryl Johnson and Caroline
work;
study and to
to this
Kim Buchanan and Cathy Law for
and computer work;
and produetion
contributions
to Carolyn
Special
work on data
Parsons-Korn
for
Perry who typed
TABLE OF CONTENTS
Page
ABSTRACT
FOREWORD
ACKNOWLEDGMENTS
LIST OF FIGURES
LIST OF TABLES
iii
iv
iv
vii
ix
Chapter
I.
INTRODUCTION
BACKGROUND
PURPOSE AND SCOPE OF INVESTIGATION
LITERATURE
REGIONAL CLIMATIC CONTROLS
Latitude
Topography
Continental
Influence
UNITS
II
DATA
SOURCES OF DATA
PERIOD OF RECORD
DATA SURVEY
Missing
Data
Homogeneity
NETWORK
III.
BASIC STATISTICS
DESCRIPTIVE STATISTICS
Frequency
Distribution
Mean and Coefficient
of Variation
Percentiles
INFERENTIAL STATISTICS
Confidence
for
Intervals
l"lean Precipitation
Probabil ity
Est j-mates
I
2
2
4
4
4
6
6
7
7
ta
I4
L4
L4
t5
2L
2L
22
36
38
39
39
42
Page
Chapter
IV.
V.
SPAT]AL PATTERNSOF PRECIPITATION
49
MEANS AND VARIABILITY
PRECIPITATION REGIONS
- Coast
Mountains
Olympic
Lowland
Puget-WilIamette
Mountains
Klamath
Cascade Range
Okanogan Highlands
Basin
Columbia
Blue Mountains
High Lava PIains
Basin and Range
I NTERSTATION CORRELATIONS
49
67
68
7L
73
74
77
79
8A
B1
Range
SECULAR CHANGES IN PRECIPITATION
CLIMATIC HISTORY
Indicators
Paleoclimatic
Data
Instrumental
ANALYSIS
Data Series
Precipitation
Trend
Fluctuations
Short-Period
of Means and
Decadal Analysis
ity
Variabil
SummarY
VI.
CONCLUSIONS AND SUGGESTIONS FOR
FURTHER RESEARCH
a2
LAA
lr3
rl3
r13
116
IIB
r18
r25
L3g
r49
L66
169
173
BIBLIOGRAPTIY
APPENDICES
A.
NETWORK OF CLIMATOLOGICAL STATIONS
A-I
B.
DESCRIPTIVE STATISTICS (T94A-T979)
B-1
C.
S K E W N E S SS T A T I S
c-1
D.
CONFIDENCE INTERVALS OF I4EAN
PRECIPITATION
D=1
E.
PRECIPITATION DATA SERIES FOR
LONG-TERM STATIONS
E-t
IC
vl-
LIST
Figure
OF FIGURES
Page
Title
I
Location Map, Pacific
Elevation
Zones
with
5
2
N.O.A.A. Map of
Oregon
Climatological
Stations,
I
3
N.O.A.A. Map of
Washington
Climatological
Stations,
9
4
Time series Graphs of
at Three Stations
5
Map Showing Network
Stations
Used in
6
Hypsometric
Curves of Regional
and Station
Topography
7
Forms of
I
Frequency Histograms of Monthly
at Four Stations
Precipitation
24-28
Comparison of Annual Progression of
Monthly Skewness at Four Stations
30
Tg
Frequency
Annual
31-35
1I
Annual Progression
of Monthly
Values at Two Stations
L2
Normal probability
Precipitation
Northwest,
Annual Preci-pitation
of Climatological
this Study
Skewness in
at
16
Topography
a Data Series
ttristograms of
Precipitation
13
I8
22
Seasonal and
at Four Stations
Percentile
Plots of Seasonal
T \ , v oS t a t i o n s
4g
43-47
r3
Map Series of Pacific
Northwest
Precipitation
Mean
Statistics:
and Coefficient
of Variation
56-57
T4
Map of Wj-nter Precipitation
Expressed
as a Percentage of Annual
5B
15
Map Series of Relative Variability
Seasonal and Annual Precipitation
63-65
vr_1
of
TitIe
Page
Geomorphic
Regions of the pacific
Northwest
with
43-station
Subset
Network
69
of
L7
Latitude
of the
Anticyclone
Eastern
18
Annual Profiles
Precipitation
of Variatiion
of Network
of Monthly
Mean
and Monthly
Coefficients
for 43-station
Subset
I9
Map Serj-es of Correlation
Coefficients
with
CorvalIis-State
for Monthly
Univ.
and Seasonal
Precipitation
and with
Baker KBKR for Monthly
Precipitation
1 C I 3 - r 1I
2g
Map Showing Network
of
Used in this
Study
L2A
2L
Map of
22
Time Series
Seasonal
Stations
23
(fgSg)
Maps of Wet Winter
and Dry
(L977) as Percentage
of Normal
Results
from
North
Pacific
Long-Term
Trend
Stations
84-99
L29
Analysis
Graphs of Annual and
Precipitation
at IZ Long-Term
in Oregon and Washington
vili
7B
Winter
13r - 1 4 3
16V
IIST
Table
OF TABLES
TitIe
Page
Itlean Annual Precipitat.ion
Periods of Record at
for Different
Three Stations
Error in Estimating
S0-year
erecipitation
from Shorter
Records in West Virginia
Relative
'Mean
Mean and Skewness for Monthty
Data at Four Stations
4
Precipitation
Comparative Frequency Distribution
for Two Sample Periods
Statistics
at Two Stations
11
L2
23
37
Long-Tern Stations,
Statistics
Descriptive
r2t
Long-Term
Trend
L27
Stations,
Statistic's
Long-Term Stations,
Decadal Statistics
on Mean and Variability
tx
15g
I.
INTRODUCTION
BACKGROUND
water has been a key erement in the hist.ory of the
Pacif ic
Northwest
and
the
region
owes rnuch of
its
deveropment to successfur
exploitation
of this
resource.
Present uses are many and varied.
As economic activity
and
population
continue
grow
to
the
competition
for
water
becomes more intense.
An expanding ur-ban popuration,
the
increase
in irrigated
agriculture
on both
sides
of
the
cascades,
the
greater
requirements
of
the
wood and
agricurtural
products processing
indusLries
and the growing
energy needs of an area largely
dependent on hydropower all
serve to focus attention
upon regionar
water resources.
The oregon water Resources board in Lg6g pubrished
a
report
titled
o
r
_
e
g
o
n
i
s
L
o
n
g
R
a
n
g
e
R
e
q
u
i
r
e
m
e
n
t
J
f
o
r
w
a
t
e
r
.
_
g
Th" study found
in arr of oregon, that wiLr be exceeded in four out of five
years,
amounts to 65.9 mirlion
acre-feet;
and Lhe totar
demand for the entire
state
courd amount to gg.4 milrion
acre-feet
in
the year
2A79, resulting
in
a statewide
deficit
of
about
14.5
mirlion
acre-feet.
similar
projections
have been made for
the
state
of washington
(e.g. State of Washington f971).
Arthough the oregon study is generally
regarded as a
generous estimate of water needs to assure that the state
wi|l.adequatery
protect its water for future uses (w.n.R.r.
L977), there is no doubt that any current probrems of water
suppry and demand can onry increase
in fuiure
years.
The
most basic aspect of water issues is that a targe number of
uses and demands are competing
for
a scarce
resource.
seasonar,
geographic
and
yeai-to-year
mardistributions
between water
suppry and water
use occur
througtrout
the
Pacific
Northwest.
water shortages occur as do plriods
of
excessive runoff.
In the humidl western parts of oregon
and
washington
economic
activity
is
not
as
waterconstrained
as it
is in the centrir
and eastern parts of
the
two states;
but
the
drought
of
Lg76-Lg77 made it
apparent that even the moisture-rich
regions are vulnerable
to the problems of water supply.
rnterrigent
planning
for
future
water
use
and
alrocation
involves a wide range of informaLion needs, not
the
least
of
which
i-s
information
on
the
naturar
variabirity
of streamfrow.
However, precipitation
is the
basic
source of water supply;
streamtrow
is its
visible
resurt.
Variability
is
an
inherent
characteristic
of
precipitation
as
it
is
of
climatic
other
elements.
a
c
c
u
r
a
t
e
a
n
d
detailed
knowledge of Lhe natural
Therefore,
of precipitation,
variability
variations
over area and over
time, must be tied in with streamfl.ow record.s for efficient
management of water, a renewable but linited
resource.
PURPOSEAND SCOPE OF IWESTIGATION
purpose
the
is
to
of
this
study
describe
The
precipitation
climatology
the
of
Pacific
Northwest,
specifically
seasonal
the natural
variability
of monthly,
and annual precipitation
over space and time.
In a spatial
dimension the study is limited
to the states of Oregon and
the inclusion
Washington with
of some data from adjacent
period
a temporal
of
states.
dimension
the
only
In
(the secular period)
instrumental
observation
is considered
essentially
the last L66 years.
presentation
a
of
the
report
of
is
the
The core
detailed
body of descrlptive
from a dense network
statistics
period,
of
climatological
stations .
cofirmon base
A
L94fl-L979, was used for this
compilation.
Development of
the data base is described
in Ctrapter III.
Spatial patterns
of monthly,
seasonal and annual precipitation
are presented
cartographically
in three different
formats in Chapter
IV
and discussed
in
terms of
A
major
climatic
controls.
preliminary
analysis
over
of changes in annual precipitation
is
time,
bottr
trends
and
fluctuations,
short-period
presented in Chapter V.
stations
A network of 7A long-term
portion
in the two states
of Lhe
was developed
for
this
study.
LITERATURE
variability
has long
of precipltation
The significance
been
appreciated
in
the
and
several
American
West
various
comprehensive
analyses
have been completed
for
and regions.
states
the earliest
One of
was [t{cDonald' s
(1956) statistical
study of aspects of temporal and spatial
variability
of precipitation
in Arizona and their bearing on
water resouces of the arid Southwest.
o!
work
has
expanded
understanding
Subsequent
our
(f900,
precipitation
variability
L972)
in the West.
Pyke's
of
geographical
work
the
distribution
on
and
seasonal
precipitation
but
patterns
was
focused
on
California
included
data
from aII
the
far
states.
western
Granger's
(tg,tl)
of
detailed
fluctuations
analysis
dealt
with
secular
precipitation
more
seasonal
and
in
lowland
California
(Byrne,
recently
ttre
on
cranger
and
Monteverdi
f982)
and
correlation
between seasonal
precipitation
in California
western
Mexico.
in the Great Basin
Characteristics
of precipitaLion
(f969).
were examined by Houghton
His purpose was to
explain precipitation
characteristics
in terms of climatic
controls
and to develop statistical
methods for estimating
ttre
long-term
precipitation
regime
at
with
stations
incomplete records.
Certainly
analysis
regional
the most extensive
of
precipitation
in
the
that
of
Bradley
American West is
(fgZ0a, L976b, L976c) in which the precipitation
history
of
the Rocky Mountain states
is presented,
That part of his
study which deals with the nineteenth
century includes data
for stations
in Oregon and Washington.
Many of
the
frequently
cited
studies
secular
of
climatic
fluctuations
in the United
are from ttre
States
eastern half
of the country
or the arid
Southwest (e"g.
Sellers 196A, Fritts
The
1965, LaMarche and Fritts
f971).
series
of anomalous winters
in the late
I97As led to a
number of studies of broad patterns
variability
of climatic
for the nation
as a whole (e.g.
Chico and Sellers
L979,
Diaz and Quayle 1978, L98g).
However, in these analyses
a few stations
only
from Pacific
were
states
Northwest
included in Lhe data network.
There has been a curiously
small amount of researctr on
the variability
of precipitation
in the Pacific
Northwest.
Several studies,
based generally
on only a few scattered
stations,
are limited
in both their
spatial
and temporal
scope (e.9. Carter 1935, Keen L937, Lynch 1948, Crowe 1963,
Church L974).
Roden's (1966) study of west coast climate
from L82L to 1964 was concerned only with temperature data.
(1948) analyzed streamflows
McDonald and Langbein
in the
the
Pacific
but
had difficulLy
Northwest
in
separating
effects
use
of
natural
climatic
variabilj-ty
from
land
alterations.
Biological
evidence (Franklin
et aI L97L) and
(
m
o
s
t
glacial
activity
recently,
and Hendricks
Sigafoos
I973) suggest that there have been important
in
variations
precipitation
Pacific
patterns
Northwest
the last
during
century.
A few excellent
studies
have focused on specific
aspects of precJ-pitation
variability
in the region.
Bates
( fgZg),
for
example, determined
of dry
the probability
years,
a. topic
of immediate interest
the dought
following
(tgZg)
of
role
6f
I976-L977.
Coakley
the
considered
climatic
variability
on stripe rust disease of winter wheat
in parts of eastern Oregon and Washington.
Sneva (L977)
(
S
n
e
v
a
and others
and Hyder L962, Sneva and Calvin
1978)
have utilized
a knowledge of precipitation
in
variability
eastern Oregon to forecast range herbage production.
Anthropogenic
precipitation
effects
on
postulated
(tglA ) for
by Fowler and Helvey
3
been
have
t h e C o l r - r : njb- a
Basin where there is large-scale
irrigation
and for areas in
(nobbs and
Washington state
downwind from industrial
sites
Radke L97g).
both
are
Results
of
of
these
studies
inconclusive.
REGIONAL CLIMATIC CONTROLS
Numerous references
are available
to describe the major
climatic
controls
which influence
amounts and distribution
of precipitation
in the pacific
Northwest.
These range from
far-reaching
studies
such as Church ( 1954), Bryson and Hare
(tgl+)
and Trewartha (fggf)
to those of more local concern
(tgOl) description
such as Lynott's
of precipitation
in ttre
(L967 )
Columbia
Gorge and Schermerhorn's
and pittock's
(1977 ) analyses of topographic effects
on precipitation.
There are at least three controls
which have a definite
influence
on the climate
of the Pacific
These
Northwest.
are:
topography and continental
Iatitude,
influence,
Latitude
paltern
airstrea.m
The dominant
in
the western
United
States
is from the Pacific
a
n
d
a
c
c
o
r
ding
Ocean
to Bryson and
Hare (tgl+)
is subdivided
portion
into
the northern
is
which
j.n winter
dominant
and .a southern
portion
from
an
emerging
oceanic
anticyclone
over
the Pacific
in
and most prominent
sufltmer.
The latitude
of the
insures
ttre
Pacif ic Northwest
dominance of ttre northern
for much of the
Pacific
westerlies
year,
particularly
during
Lhe cooler
arrives
season when it
on the
quite
west
coast
cool
with
a near
moist-adiabatic
Iapse
rate
and with
high
humidity
to a considerable
depth.
portion
The southern
of
the
ttre
westerlies
subsides
from
anticyclone
Pacific
which
migrates
the
northward
during
sunmer and is
responsible
for
of
a shorter
sunrmer season
drier,
more stable
air
and modest precipitation
e
v
e
n
totals,
along the immediate
coast.
Topography
(see
Figure
f)
The Coast and ttre Olympic
mountain
ranges
are the first
to intercept
moisture
laden marine
air
masses moving
inland
from the Pacific
Ocean.
Ttre cooling
of air
masses as they
ascend
produces
the
western
slopes
some of
the
heaviest
annual
precipitation
in
the
and
naturally
United
States
Iessens
the amount available
farther
inland.
to Lgg
Seventy
mj-les inland,
the Cascade Range, paral-lel
to the Coast Range
and
to
the
the
Puget-Willamette
Trough
situated
between
ranges,
plays
and
an important
role
in modifying
temperature
precipitation
and essentially
a wet,
divides
into
the region
gre€n
nildr
west
and
a
semiarid,
east.
brown
cooler,
Figure
t.
Map of the pacific
showing
Northwest
Elevation
(white
Zones z 6-LOAA feet m. s.1.
shading) ;
(medium shading);
Lgg0-s0gg feet
and above 5ggT feet
(dark
shacling) .
However, because the moisture
content
of
the marine
air
masses is greatry
reduced by passage over the coast Range,
the precj-pitation
on the western slopes of the cascades is
lessened and decreases very
rapidry
once the east
side
descent begins.
situated
along the boundary between oregon
and- washington,
the
corumbia
Gorge has
cut
its
gorge
entirery
through the cascades and offers
easy p.ssagJ
for
marine air from the Pacific
which moderates tempLratures
to
the
east
in
both
winter
and sununer and through
which
continentar
air
occasionalry
passes in reverse to produce
extreme temperatures
in the western varleys and the portland
metropolitan
area.
Continental
Influence
The sharp
decline
precipitation
in
and the
colder
winters
and warmer summers experienced
east of the cascades
resurts
from the barrier
effects
of the ranger €rs noted
above, and arso is due to the increasing
distance
from the
moderating influence
of the pacific
ocean.
rnterior
basins
and varreys
may experience
temperatures
werr above rago F
when the Pacific
anticycrone
shifts
inrand during the sunmer
and temperatures
welr below go F during invasions
of porar
Canadian air during the winter.
The combined influence
of these three dominant climatic
controls
in the Pacific
Northwest produces the variations
in
annuar precipitat.ion
that are greater
than anywhere erse in
the
eontiguous
48
states.
severar
rn
areas
annual
precipitation
ranges from less than 2a inches to over Lsg
inches within
a distance of 6a miles.
unrecorded extremes
are undoubtedry higher.
rt is the purpose of this report to
describe characteristics
of this natural variability.
UNITS
Arthough
metric
units
have long
been the
standard
language of scientists,
ttre voruminous crimatic
data for the
united states are available
primariry
in English units.
rn
this
report,
therefore,
the
English
units
are
used
throughout.
rn addition,
we feel that the majority
of users
this
of
report
wirr
be persons
who are
not
research
scientists
and who are likery
to be more familiar
with the
traditional
English units.
II "
DATA
Given the inherent variability
of precipitation
over
time
u
n
9
s
p
a
c
e
m
e
a
n
i
n
g
f
u
l
'
.
and
regional
descriptions
" i i " oan = r a r g e
c a n b e s t b e m a d e" ow, nf ti n
data base
uliform
::?:""_":.:-i_:g,u_
based on
dat.a
rg4a-Lg7g.
c i r . n ep e r i o d .
assembred
The primjry
i- pulirl;
f or
a
Al-year
purpose of
-ilrhwesr
base
per iod
S O U R C E SO F D A T A
The main sources of climatic data in the
united states
t
he publicarions
of rhe Narional climatic
?rg
center in
Asheville,
North carolina.
Data are compiled for a dense
network of cooperative climatological
statsions throughout
the nation and pubrished on a state by
st,at,ebasis (Figures
2 and 3).
other
useful
precipitation
summaries have
been
compiled by.various
agen-cies in t,he pacific
N
o
r
t
h
west
concerned with
study of regional vrater resources.
!
h
"
The
River Forecast, cenrer i; porrlSnd is able
to supply monthly
rainfall
totals for several stations i; the region
for the
I the Pacific Northwesr River
muLti-volume study entitled
the Columbia Basin States. "
:e modest scale are available
and federal
agencies;
for
example, data from a network of
g
a
g
es
rug"-precipitation
i n m o u n t a i n o u s a r e a s a r e m a i n t a i-nset o
- o -t v a n " N a t i o n a l F o r e s t
Service.
several of these data sources were consurted,
but for
the
purposes of
thi s
study
it
w a s d e ci d e d
Eo rery
glglusively
on official
oari obrained from rhe Narional
climatic centerMagnetic computer tapes, one each for che
o r ]r w e r e o b t a i n e d .
The tapes
rcipitation and temperature at
i e d a t a a r e a l s o a v ai l a b l e i n
lr nr rcl vl ur rdr eu se . '
a n n uuaarl
summ
maarrrieess. .
microfiche,
are maintained in
record at
individual
C ll ii m
maat tool ol oq-gi -cE
i acElahl F - bDo aa
u tntaad ,-
copies,
*o"L of
the
major
ttrqJvt
r.h
r hi c
i nhh
w
or
r iabt r a r i e s
a
The publications
have the
itional
information
such as
ies.
These station histories
the length of rel iable
stacions.ning
o
oil
(,
t{
o
a
r
;
t
:
1".- z!
!
i
o
.r{
{J
o
+J
(rj
fd
U
,rl
o
o
o
F.{
F
I
D1
{J
d
.Fl
-q
U
r+{
o
p{
d
E
q
:
z
0:
--i<::
p .
.tr:
C\
ql
l-{
ot
.-l
h
1
I r
i r
q ?
t+
E
l r
: i
3 9
a
B
- F
8
- ---c:--
_9
E
: t
:E
1
I
I
;
3
io
o
d
s
t
s
l!"
t
o!
t i
f--------;--.=.
" €r
S
: l
55
E :
o
C' . +
.
a + - " :E E
t F - t
. . " e 4 i! i I
c
o
+,
o
.Fl
o
rd
B
a
c
o
.Fl
\i
+J
d
+J
a
F-{
d
(J
..J
o
o
FI
jA
+)
F4
U
tl-l
E
4
Qt
o
z
j_
-;---
': c zo'
F
c)*
Z.
FFs
a
< ,
>
2
N
F
2
o
E
=
F
o
co
0)
!
FN
.1
G,
PERIODOF RECORD
T o m a k e m a x i m u mu s e o f t h e a v a i l a b l e d a t a a n d t o d e f i n e
patterns,
spatial
it
is necessary that data from as many
the
and that
stations
analysis
as possible
be used for
I e n g t h o f t h e c o m m o nr e c o r d p e r i o d b e a s l o n g a s P o s s i b l e '
the longer the
Obviously, these two needs are in conflict;
per iod
continuous
number of
t,he f ewer the
of
record
precipitation data series available.
Accepted convention, as adopt,ed by the World lrleteorological
normals is
Organization (w.M.O.) for climatological
the 30-year period currently defined as the years I94I-L979,
Appreciable variations
soon to be updated to 1951-L980.
to anot,her and tttitchell
occur
from one 30-year period
be
( 1966)
c1 imatic
suggests
that
arnong oEhers
data
s u m m a r L z e df o r a l o n g e r s t a n d a r d i z e d p e r i o d o f y e a r s w h e r e
length of record permits.
an initial
inventory of Oregon and Washington
After
data
it
was decided to
utilize
a 40-year standardized
period, 1940-L979. More information is included than would
be in a 3O-year base period; but use of more than 40 years
would cause a rapid reduction in the number of continuous
complete geographic
r e c o r d s a v ai l a b I e
and thus
a less
represenEation of the region.
The choice of a base period
ending in
I97g or
I98A) may seem
L979 (as opposed to
inconsistent
normals; but several
with other established
climatologists
have recommendeda change from the W.I't.O.
practice of defining decades.
Instead of counting decades
from year one to year Een (e.9. 196f-I979) | it would be more
convenient, if decades were counted fromm zero to nine (e.9.
and che
is
choice
arbitrary
L 9 6 g - L 9 6 9 ).
However, the
decision here was due to the simple fact that at the time
this study commenced dat,a for L98g were not yet Processed
and published.
justification
a 40-year
for
the use of
Sufficient
per iod can be given.
annual ser ies
Several long-term
generated for Chapter V of this report are used Eo illustrate the relationship
between record length and long-term
mean, in this case a 96-year period, 1896-1979. Data frorn
three of these stat.lons (Table 1) represent a range of c1iin
north-central
matic conditions:
a semi-arid
station
(
H
e
p
p
n
e
r
)
;
a
h
u
m
i
d
s
t
.
a
t
i
o
n
i
n
w
e
s
t
e
r
n Washingcon
Oregon
(Centralia);
in southand a moderately subhumid station
s
e
r
i
e
s
d
o
s
u
PPort, the
western Oregon (Ashland).
d
a
t
a
These
choice of a AT-year sample, at least in terms of the ability
record
to
the
As the
length
represent
mean.
96-year
a
increases the long-term mean is more closely matched
relationship
that holds through 4A years at Ashland and
Beyond 4g years little
1s gained by using a
CentraLia.
l o n g e r b a s e p e r i o d e x c e p t p e r h a p s a t H e p p n e r, t h e d r i e r
station.
Relative errors are generally greater in areas
10
Table 1;
Period of
Record
1975-t979
(5 years)
I{ean Annual Precipitation
for
Different Periods of Record
(Expressed as a Pereentage of
90-year lvlean)
Ashland
Heppner
Central ia
88.7
98.7
95.8
r 9 7s - r 9 7 9 ( l A y e a r s )
96"4
9 9" 6
r01.3
196s-r979 ( 1 5 y e a r s )
95.8
99.3
101.6
1 9 6 s - 1 9 7 9( 2 0 y e a r s )
94.9
98.1
103.3
195s-t979 (25 years)
94.8
LgA.T
103.5
1 9 5 s - 1 9 7 9( 3 6 y e a r s )
96.1
IgO.B
L A 3" 8
1945-L979 ( 3 5 y e a r s )
97.9
LOI.3
1a2.7
1 9 4 A - 1 9 7 9( 4 0 y e a r s )
IAg.3
101.9
rga.6
193s-r979 (45 years)
LA6.4
99,5
I g a" ' l
L 9 3 A - r 9 7 9( 5 4 y e a r s )
98.8
9 7. 8
rag.3
1925-r979 ( 5 5 y e a r s )
98.7
96.9
99.2
L 9 2 A - r 9 7 9( 6 9 y e a r s )
98.2
9 7. 3
99.3
1915-L979(65 years)
98.l
98.9
99.8
19Ig-I979 (7A years)
98.7
98.1
r00,0
L905-r979 ( 7 5 y e a r s )
99.2
98.1
L A O" I
1 9 g a - L 9 7 9( 8 9 y e a r s )
99.9
98.2
IA0.4
1 8 9 5 - 1 9 7 9( 8 5 y e a r s )
99.3
98.7
r09.3
I89s-r979 (96 years)
Lgg.g
Lgg.g
rgg.0
il
precipitation
lower
of
precipitation.
smaller
and
Lee (DAA ) has presented
long-term
attempts to estimate
records
basis
of shorter-term
region (taule Z):
Table
2z
in
areas
of
higher
illustrate
that
statistics
on the
average precipitation
a hunid
i,n West Virginia,
S0-year Mean
Error in Estimating
Relative
R
e
cords in West
from Shorter
Precipitation
Virginia.
Interval
( years )
5
LA
15
26
25
3g
4A
Mean Error
E
1 7. 6
11.3
8.r
6.3
4.5
3.7
2.4
Rapge
Error
(958 confidence)
14.1
9 .6
7.g
5.5
3.8
3.2
2.9
2 1. 1
l-2.9
9.2
7. L
5.2
4.3
2.8
advantage
of
emph4size the
exanples
these
Both of
as opposed to a standard
record
a A|-year
working
wittr
period
the
progressed
study
this
record.
As
3a-year
the
for representing
Lg4b-Lg7g proved to be a good selection
precipitation.
There is no
in regional
range of variability
in a more stable
would result
a longer
series
doubt that
would be more
and sample statistics
frequency distribution
Yet as illustrated
statistics.
of population
repiesentative
of these three
series
of annual precipitation
by a plot
almost
(figure
the period
194g-L979 includes
stations
4),
the last
within
range of extremes experienced
the entire
to be true
showed this
years.
ninety
Subsequent analysis
Northwest.
in the Pacific
stations
for many climatological
between our two criteria,
Thus, based on a comPromise
the 40-Year
availability,
mean and data
the
of
stabitity
far
period
as the
"normal"
period
L94A-L979 was selected
the
as such ttrroughout
be referenced
and will
this
study
report.
12
Centrolio
I
Meon = 45.49 inches
s
a
B
E
6
+
9 s
B
E
q
I
e rilC6
r e<o
tgoo
I eoo
t Ezo
t-eeg
E
0
r
3
E
- 9
o
=
Ashlond
e
Meon = 1957 inches
@
@
3 a E
{ l N
o
-z 9
E
o rLea--
Fiqure 4.
erecifitation
I gao
Time Series
Graphs
at Three Long-T-erm
l3
of Annual
Stations.
| 470
' gBE
(water Year)
Data in Inches,
DATA SURVEY
and the
Wastrington
in
Oregonn
Over
3AA stations
adjacent
areas of California,
Nevada and Idaho have records
AI1 were inventoried
extending
through
the normal period.
to determine the amount of missing data and the reliability,
or homogeneity, of the record.
Missing
Data
r:sed by
data,
the procedure
to missing
With regard
(tglOc)
any station
witn more than
Bradley
was followed:
absent vras eliminated.
percent
five
of the monthly values
were
values already in the record as published
Interpolated
were made in
assumed to be correct.
However, exceptions
be combined to
records
could
situations
where
station
produce a continuous record.
to have
is desirable
it
analysis
For climatological
stations
for
the
Mj-ssing data
continuous
data
series"
two
commonly used
of
by
one
estimated
were
selected
One is
techniques,
both using data from nearby stations.
Of measurements from the
and correlation
the
regression
a
station,
from a nearby
data
with
station
of
interest
between the
exists
reliable
technique if a high eorrelation
method of
is
the normal-ratio
technique
two.
A simpler
is
value
(tgSZ)
in which the missing
and Paulhus
KohIer
three
surrounding
from
average
by a weighted
estimated
the
employed,
were
both
methods
stations.
Although
data were
suf f icient
if
method lrtas preferred
normal-ratio
percent
of
with more ttran five
available.
Since stations
monthly values missing were excluded from the network, it is
affected,
are not noticeably
statistics
felt
that resultant
for seasonal and annual totals.
especially
Homogeneity
The second problem that had to be addressed j-n the data
o'f the
or homogeneity,
survey was that of the reliability,
instrumenLal exPosures
records.
climatic
Station locations,
by
been determined
standards have generally
and observing
requirements.
Thus, changes in these
immediate operational
histories,
aII
station
parameters
nearly
are
conrmon in
(Landsberg
L96g).
urban
areas
expanding
in
especially
to
p
a
r
t
i
c
u
l
a
r
l
y
s
u
s
c
e
p
t
i
b
l
e
a
r
e
r
e
c
o
r
d
s
Precipitation
s
u
r
f
a
c
e
a
s
p
e
c
t
,
s
u
c
h
a
s
e
x
p
o
s
u
r
e
,
d
e
t
a
i
l
s
l
o
c
a
l
changes in
s
t
a
t
i
o
n
s
a
r
e
s
u
l
t
r
o
u
g
h
n
e
s
s
.
A
s
heating
s
u
r
f
a
c
e
and
are
records
homogeneous precipitation
exhibiting
truly
f
i
n
d
.
t
o
difficult
if not impossible
14
various
statisti-car
methods have been deveroped to
test
crimatic
records
for
tromogeneity.
The doubre-mass
plotting.
technique
(xohler
LgLg) is one conmon method for
correcting
a
but
depends on the
-non-homogeneous record
reliabirity
of
station
records.
Barger (Lg6g)
" nernr o
fel-t that adjustm
t , r nodf i t rag r e c o r d c c i u r d n o t b e
made without
ross of some of the statisti""r
prop"rties
of the station,s
rainfarl
series.
rt
is not unreJsonable to expect that
many smarl cli-matic
changes might be introduced
in such a
procedure.
Therefore,
no attempt
has been made in this
study to adjust records for inhorn'oge""ity
rnstead,
station
histories
were studi-ed carefurry
for
changes in - location
and exposure.
Station
m
o
v
e
s
o
f
l
e
ss
than two miles,
i f ' a r it ne fr raet iqoune n t , ' _ "w
r -e-r"e* p tcsou nr es i d e r e d a c c e p t a b r e
if
no
serious
was
implied.
Likewise,
elevation
shifts
of
tess' than
LUa feet
were
ng frequent
and/or
excessive
and elevation
were rejected.
rs to determine homogeneity is
n of basi_c statistics
and for
)n correlations.
For the more
such as the determination
of
slow cl-imatic trends in Chapter
V station
records have been
scrutinized
even more closely.
NETWORK
completion
yierded
a finar
wetter
probrem
;:i::!:i
portion
( pyre
have
of
the data
survey
as descri_bed above
network of
244 crimatorogi_cal
stations:
,ton and ZL in adjacent
areas
Nevada.
These latter
were
>recipitation
characteristics
rt of all stations,
along with
rgitude and elevation
is given
.etwork appears as Figure 5.
Lo
represent
the
climatic
--ver, the most unsatisfactory
Il- number of high
elevation
' sj - s .
This
is
; persistent
-ysis throughout
tha American
homogeneity probl_ems involved.
rnges in mountainous terrain,
'm wind
velocities
and the
raj-nfal_I during much of the
of
the
year
compounds thJ
honogeneity
1966 ) .
rn addition
*o.t
J'- air"-"io,rntail
short
records
and missins
pr""ipitarion
ITh" best
source of data for precipitation
in nountain
watersheds
is the series
of snow survey reports
pubrished
by the U. S. SoiI Conservation Service.
15
-c;;--
-'BE5*
azsoz
6€ao
'
doTE
-ar',
*157
'697d
*512"
.8059
"
.1a""
at€50
'i123
ag37!
Jl92
.ttt'
t
^2675
'_-_^
ar"rafot"
i""
ir3s6
*na,
*L10
6r'0
"
.-"
.-*
'49x
aeo'a
.3!2e.e238
]@'
o9ol2
.1672
-13 soc
629Gaalr2s3
86 0946 G.tr ';t;.rsil
4ara
!,*
I:.
'9327
aJo"
.2614
a3502
.ao3s
ateoo
o4C70
a2505
ttoeso
a5425
^
rL^-f'€5
t@
a6r8e
4ro"
J6es
.o,
aroao
aalSa
----'_-
.3222
,,,?i3t@t8:--,
fl._:ilfi;
jino
a646s
J562
f'3s4
aa2o7a!7aa
-
,168
.93.2
6
* rsl
a65a0
rP"t
a6734
Jri'o'o
da60
ar566
.to1ru"
.E6Be
aag6g
or",
a433a
a354€
.!8os
gro
.7e6c
arc59
l5lr3
I
lffi
.3970
o'6a
lltt
4111
JTO5
*te.,
a663a
a4622
a6726
a1g2a
a4746
a2fi2
B€33.
dor97
at5@
J2n
a2605
fE62
t32
,rgo
*!,1|,
a SOAO
aPl39
o35a2
ta:
.2bg
1Atl
t
7052a
53€2
ap8s3
'02't
I' 069a
tE9t
oqgoz
"r"l
a62r3
azero.2465
rr1l
a-6t7a
d6414
a93A
733'
*
a1546
ar68
t rga€
(":'..
f'*
aa9o7
atSI
a12O'
a3445
i'5429
a5a2a
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a
14506
4403
a257!
Figure 5.
Network of crimatologicar
stari-ons Used in this
study, L94a-r979 Normal period.
station
Descri-ptions are in
Appendix A.
lilote:
Those indicated
with a star are a 43station
subset used for later data summaries in this report.
l6
is interesting
to see the relationship
between the
It
elevat.ion
range
the
the
region
and
of
under
study
representaLiveness
average
of
the
clata
network.
The
elevation
the
in
of
sbations
Lhe network
is
L562 feet
m.s.l.,
ranging
from 56L6 feet
at Hart Mountain
Refuge in
Oregon t-o near sea level
costal
stations.
This
at several
network
can
be
represent
a
topographic
considered
to
(eradtey
surface
across
the
region
and a map was
L975c)
(area-elevation)
drawn
accordingfy.
curve
A hypsometric
was constructed
from the map.
was drawn
curve
A s j-milar
( see
f rom
the
actr,ral
topographic
state
surface
of
the
a
Figure
of
regional
shows
topography).
I
Figure
6
comparison
by the
between
the two surfaces
as represented
hypsometric
curves.
indicates
that
zones are
elevation
It
increasingly
under-represented
at higher
elevations.
Since
a general
increase
in precipitation
elevation,
occurs with
any derived
estimates
necessarily
of areal
rainfall
would
be on the
problem
low side"
the actual
of sampling
This
climatological
diversity
the region
be borne
within
should
in mind by the
analysis
reader
throughout
subsequent
data
presented
in this
report.
monthly
The basic
data,
are
of
then,
the
sequences
rainfall
the
totals
in
at
climatological
stations
244
p
e
r
i
o
d
t
h
r
o
u
g
h
Pacific
for
Northwest
the
"normal"
L94fr
(WY),
aecording
1979.
Data are arranged
to the Water Year
through
I October
a time frame used routj-nely
3g September,
in hydrologic
both
and climatological
studies;
for example,
( fgZg)
(
t
g
O
t
Bates
this
and
f
o
l
l
o
w
e
d
Schermerhorn
)
convention
p
r
e
c
i
p
i
t
a
t
i
o
n
in their
studies
i
n
of
Oregon and
Washington.
with
a
h
y
d
r
o
l
o
g
i
c
From
standpoint
it
coincides
the annual
it
regime of most rivers
and, climatologically,
y
e
a
r
allows
the entire
i
n
o
n
e
winter
season to be included
rather
than
being
artif
c
a
l
e
n
d
a
r
icial-ly
separated
by the
year.
period
the
Thus WY I94A
is
1939
from
I
October
through
from
1
3A September
extends
L94g and WY 1979
October
L978 to 3g September L979.
and
Monthly
totals
are also
summarized
into
"winter"
totals.
is
the
"summer"
this
Throughout
study,
winter
seven month period
from October
through
suflrmer the
Aprit,
period
five
month
May through
September.
Specifically,
"winter
L949" means the period
1 October
1939 to 3A April
(WY) totals,
I94A.
trlater Year
a winter-sunmer
then,
are
sequence.
for
The choice
of
a seasonal
is
logical
definition
several
reasons.
markedly
differ
Synoptic
weather patterns
between
and
winter
are
obviously
summer,
althougtr
there
transition
months dif f icult
to classify.
Winter
.orecipitation
throughout
the region
extensive
is associated
with
cyclonic
Pacific
results
storms,
while
sufirmer precipitation
predominantly
Iand
from
convective
activity
over
heated
17
ol
c)1
.-l l,r
so
+rc
rdF
o
c
o
o
o
o
B
e co
r.)
l \ t
-c
e
0
c
o
o.
,l
o
b
l-
o
o
o.
o
- 6
E
9
q ,
o
c
o
o
o
\
O
e
o
o
-o
o
e
.9
o)
o
L
r+n
o
+
C
o
g+l
{ J O
a z
Fl
Frc
-ro
H'Fl
+J
i J d
U' +J
o(,)
i.{ O
, 9
(Jd
a I
O Q {
..{ d
{J t4
d o |
> o
O 9.1
tI]ts
I
(0-{
o d
k c
,<o
v.A
(''
O O
.r{ C
|]
+ J g
C J O
Eo)
o 3
n+J
P{o
hca
H
|J
L
o
G
o
o
q
€
o
o
o
o
o
o
(\|
rt'
( t e s t lu o l l o ^ o l f
18
Eq
o
. a
\ct.Fl
! h
o d.c
t-{ O{ O{
5 : i - 6
lno u
..{ O Ul
E { O
O Q {
4J EN
surfacesrn the consideration
moisture suBply
and crop water
d e m a n d s t h e a- iovfi.srie' ogni o n ai sl
also
rogicar..
Agriculture
in much of the pacifis
Northwest is dependent
on irrigation
water from mountain snowpacks which corJect,
during rhe winrer monrhs. Finarrt,;ii'
official
srreamflow
records mainraiTqq
U
.
S
,
G
e
o
l
o
g
i
c
a
l
s
ui"Ly
are
p r o c e s s e d a n d p u b l i s h.ebdy - il nh e t h e
water y"", framework.
l9
III.
BASIC STATISTICS
The primary
objective
analysis
of
is
climatological
(fhom 1966).
cIj-matological
prediction
Lackj-ng the ability
to
forecast
future
climate
the
on any meaningful
scale,
careful
preferred
evaluation
of pasL data
method.
is
the
In
the
course
of
this
study
set
of
basic
a detailed
statistics
were
calculated
from
and
seasonal
monthJ-y,
annual precipitation
in this
data series
and are presented
chapter.
represents
This material
the core of the report.
Basic
descriptive
and annual
statistics
for
seasonal
j-n Appendix
series
are
included
d
escriptive
B
a
s
i
c
B"
statistics
for the monthly
in
data series
are not included
their
entirety
but
only
for
s
u
b
s
e
t
o
f
t
h
e
a 43-station
network,
selected
precipitation
to
represent
character'istics
throughout
the
Figure
see
5) "
Pacific
Northwest(
These
statistics
are
also
in
B.
Monthly
Appendix
statistics
for
any other
network
may be
stations
in
the
obtained
from the authors
upon request.
proce<lures
The
following
discussion
of
statistical
used may be elementary
is
to most researchers.
it
llowever,
intended
that
these data be available
of
for a wide variety
applications
and to
a wide
many with
variety
users,
of
Iittle
knowledge of statistical
methods.
DESCRIPTIVE STATISTICS
Basic
statistics
fall
into
two categories
one of
descriptive
and inferential.
between the
The distinction
two is important
for both
the researctrer
and the practical
user.
The aim af descriptive
a
is to describe
statistics
data
series
numerically
and spread
so that
i-ts magnitude
can
be
expressed
concisely
and meaningfully.
The most
important
aspects
of precipitation
mean or
data
are their
average
size and the extent
and nature
of the spread of the
data,
the variability
about the mean.
The mean
x
(I)
is
L 1
defined
as:
(r)
= n (_xi
where
The statistic
of values
about
defined as:
n is
the
number
of
observations.
used to describe the spread or deviation
(s),
the mean is the s t a n o a r d d e v i a t i o n
4:ut-t1
{2)
n-l
21
calculatecl and presented
statistics
Other descriptive
i n A p p e n d i x B a r e t h e m a x i m u ma n d m i n i m u m v a l u e s ( w i t h y e a r
of
of occurrence for Seasonal and annual data), coefficient
(Cv) and percentile values.
variation
Frequency Di str ib_qqion
Eool for
is
the
basic
The frequency dist.ribution
Histograms of the
describing and analyzing a dat,a series.
i
amounts are an nformative way of
frequency of precipitatio4
Skewness(Sk) is a useful measureof
depicting variability.
It
the symmetry (or asymmetry) of a frequency distribution.
h
e
r
e
in
i
s
btays and
of
a variety
can be expressed in
calculated as follows:
sk = {f!.-i)zrl3
(3)
n
the tail extends farther
In a negatively skewed distribution
toward the small values; in a posit ively skewed distribution
Zero
the ta i I extends toward t.he larger v a l u e s ( F i g u r e 7 ) .
o f a s y n m e t ri c a l c u r v e r e p r e s e n t . i n g a
skew is characteristic
normally dist,ributed variable.
Symmctrical
Slight positivc,skewness
Median
Figure 7.
Types of
Frequency Curves.
?2
Slight negativeskewness
skewness were carculated
for arI
.Monthry varues of
stations
and those for the 43-station
subset are i_ncruded
in Appendix c.
F5-gure g irrustrates
frequency histograms
at four of these stations,
selected to represent a range of
moisture
conditions.
Newport is
a wet station
on the
oregon coast;
Forks 1 E is a wetter
station
on the west
side of the Olympie peninsula;
Heppner and Malheur Refuge
HQ are two rerativery
dry station;
in centrar
oregon witrr
differences
in elevationand exposure.
The ordinate
on
each graph is the number of cases that
falr
within
the
class
i-ntervals
whose midpoints
are
designated
on the
abscissa.
Mean (f) and skewness (S:<1 are labeled on each
histogram
and are corlectecl
in Table 3 for
comparative
purPoses.
Table
3:
Mean and Skewness for Monthly
Precipitation
Dara (WqT-tg7t)
(data in inches)
.
October
January
LI.47
r.a6
16.93
a.74
8.L4
a,26
2.4L
A" 9 9
x
SK
6.62
4.55
r4.89
9.44
4 .8r
a.43
g.85
L.4g
x
sk
1.19
L.ga
L.43
I .15
t.25
a.a5
A.37
L.A3
Malheur
x
Refuge He SK
9.78
I .69
L.A4
I .48
a.59
r .41
9.29
I .62
Forks
I
E
x
sk
Newport
Heppner
April
July
With
regard
to
these
graphs,
it
can
be
seen
immediatery that as the rikelihoodof reachi-ng an upper or
lower limit
increases,
the frequency distribution
tends to
become skewedr of
asymmetricat
(iriffiths
rgg2).
This
phenomenon is_ particurirly
apparent in monthry histograms.
rn
single
month
the
ti:<etitrooa
of
rittre
?ny
or
no
precipitation
exists,
certainry
a very remote possibirity
in the winter months in the western part of the regi_on
but
m-ore likely
in the suflrmer months and for arr monttrs east of
positivery
the
cascades.
skewed distributions
are
the
result.
Exceptions to this are few as seen in Appendix c.
Arthough
the carcurated
varues
of skewness are probabry
fairry
repr:esentative
there
is no doubt that
a sJmpte of
many more than 4a observations
would arrow one to determine
the true
frequency
distribution
with more confidence "
A
further
irrustration
of
the
difficulty
in
interpreting
monthry distributions
from this
smalr sarnpte is giv6n by a
comparison of the monttrry progression
of skewness between
23
Figure
Frequency
Histograms
of
lvlonthly Precipitat.ion
Ne\rrport,
Forks
Note:
(L94A'Lgl9)
z
Oregon
18, Washington
Heppner,
Malheur
8.
Oregon
Refuge HDQ, Oregon
wilth{n
fafl
is tlte number of cases that
The ordinate
on
designated
are
vrhose midpoints
the class intervals
the abscissa.
Data are in. inches.
24
8r
?da
+;g
=
*
g
g:
)3,fr
.!I
=H
B"
E
o
o.
'
o
z
r+
l-+
h+
Fa
,.
Fs
l-+
Fa
g:
*;g
=v
E@-
!
]+
Z*-
q
<o
-o
oc
n
E;
.ti
ca.
s-g
zV
6/
I
0.
rl.$;
qJ
,tt
.Y
o
u-
<6
to
te
c+
s=t?g
=
=*
't
+
26
>:
9Ee'
=;
=;g
l-q.
l-q
5$9
.=
zH -v-
=E
=
l-s*.,
*t
l-,;'
to
o
E
o.
o.
o
-
Es
$1
=.i
E;g
*;g
EI,i6
=v
=g
;
e
r
9
o
o
6
r
_
i
;
E
.
or
3s.l
=;2
=
- v
HE
=
:
+,:1E
=v
o
o
c)
o
D
o,
E,
f
0)
E
=
5P;
e;E
=8
=:
.;=
:9'
ey
Heppner and Malheur Refuge HDe, the two dry stations,
and
between Nerrport and Forks r E, the two wet coastar
stations
(figure
9).
This progression
should be nearly coincident
for each pair;
that it is not suggests the need of a larger
sample.
Of greater
interest,
because they better
represent
the
true
population
or
distributions,
the
frequency
are
histograms
of
seasonal
and
series.
annual
rainfall
skewness for seasonar and annual series at alr
stations
is
also listed
in Appendix C and frequency histograms
of the
four previousry
identified
stations
are depicted
in Figure
IA.
It is normal expectation
that rainfatl
climatological
series
(e.g. months) for which the mean
for short periods
is small generalry
have positivery
skewed distributionsr
ds
j-n which several months
noted above.
For seasonal periods
are combined the mean increases
and skewness decreases or
more nearly
approaches
zeto.
without
e:tception
Indeed,
seasonal varues of bhe statistic
are croser to zera than
are
varues
of
the
statistic
for
months
the
individual
within
each season.
yietd
Thus, these series
a smoother
and more nearly normal distribution.
To illustrate,
consider
Newport with a
T-year winter
mean of 59.96 inches, the driest
winter being 26.7a inches
in
and the
I977
wettest
inches
in
89.31
L974.
The
likerihood
of no precipitatj-on
at alr in a winter
season is
negligible
and
the
frequency
distribution
nearly
-O.II).
=
(Sf
symmetrical
contrast,
mean sunmer
In
rainfall
is considerably less, IO.35 inches, the likelihood
of
values
near
zero is
greater
and there
is
distinct
positive
skewness (St< = I.A5) -- that is, the dist.ribution
tairs
of f
toward
higher
values.
distributj-ons
Annual
closely parallel
those for winter.
geographic
The
pattern
of
and
annual
seasonal
frequency
distributions
for precipitation
in the pacific
Northwest
is
particurarry
interesting.
e.xpected
The
inverse
rerationship
between mean and skewness, so evident
when considering
the length of the averaging period
at one
station,
is not so evj-dent in a spatial
dimension"
winter
and annual series yield
consistently
row skewness values,
negative
as commonry as positive.
The pronounced positive
skewness of arid
and semi-arid
rainfall
in other
series
regions such as the American southwest (see,
for example,
McDonard 1956) is not evident here.
from the
Data series
drier
stations
in
eastern
and washingLon
are
oregon
generarly
as near-norrnar as are those from ttre wet western
part of the region.
Note, for example, Heppner (annual Sk
= -A.Ag) and Malheur Refuge HDe (annual Sk = -A.B).
In the sunrmer season, however, distributions
exhi_bit a
distinct
positive
skewness; but again the expected relationship
between mean and skewness does not hold.
rn fact,
29
FfiI(8
I E Y8
g.t
2.6
2.t
I
rl.6
E
ta
,
lf
Er., V
8
(.
/>-T=''tv*.-.*/""''
- - t'- -.-
o.6
4.9
l
l'-"'s
n'
,l-.,Lr__-
FnfSlE
|
8
,'
- 3/-
i
i
/' -"*-*---.
,r''
- -' ,'i'*-#--\-
r
i
('
NEUPMI
-t.6
-t.t
F
l
t
lrofitl
A
l
l
J
J
A
S
I.IONTHLYSKEIJNESS
HEPPNERVS MALHEURREFUGE HO
4.9
3.5
,
3.A
s
K2.5
E
l{
!"'u
s
s
-
MALHEUR
REFuGE
Ho
A
/
, )
, ' t . .
/
-.
t.s
].r
-rr,
.,
\
\
\
-/
; ,
l.o
4.5
g.o
Figure
Skewness ,
F
Comparison
9.
l94A-L979.
I
of
.
I
l.IONTH
Annual
A
M
.
Progression
J
J
of
A
S
Monthly
Figure
Frequency
Histograms
of
Seasonal
Forks
IE,
Heppner,
rilote:
and Annual
(p+a-w7e) -.
Newport,
Malheur
Lg.
Precipit
tion
Oregon
Washi-ngton
Oregon
Refuge HDe, Oregon
The ordinate
is ttre number of cases that farr
Lhe class
intervals
whose midpoint.s are desi
on the abscissa.
Data are in inches.
ittr in
nate<1
E:
EB.
l.;E
6-y
zs #
f+
<o
*
s+
<o
E;
Ea"
2e8
-.=
=-*
$
<$
g-'
-o
i ' e
r .
32
ioe
J
'..
-l*1>
Io*
l-o*
@a
=6v
t
r%
33
"
=d
EE;
'.v
AY
g"
-c
+
ol
Q.
s.
4n
e?
5e
34
|-+c
l+
c
I-.s
I
*q. :
o
4
:"
Il-+,.
l-e"'
-
-.,_---j
a
6
I
o
o
D
o
e,
l
o
.G
o
=
.FT
-ifi
b
Eie
o
:'
I?
c
Ib
l_+
a
larger values of skewness are found for series in the wetter
western part of the region.
This apparent anomary is due in
part to a weakness in the seasonar definitj-on
used for this
study.
Precipitation
in
t"tay and
September
is
highly
variabre
from year to year as extratropical
storm tracks
respectivery
withdraw
from and approach
the region.
The
area west of the cascades experiences
more precipitation
at
these times than the area east of the cascades
a
n
d
M
a
y
"
september rainfarr
tends to dominate in summer totars
for
the western region because the other suflrmer months are quite
dry.
Conversely,
east of the Cascades May and June are
reratively
wet months and, as discussed in chapter rv, are
not as variable
from year to year as might be expected.
In Table 4 is a comparison of frequency distribution
statistics
between the 4a-year sampre and an approximately
96-year sample at Heppner and Newport.
It can be seen that
sample size
has
a surprisingly
small
effect
on these
statistics.
the
For
summer series
there
is
a slight
reduction
of skewness with the larger
sample at Newport; yet
at Heppner skewness is essentially
unchanged.
Overal_l, it
is apparent that the frequency distributions
and
of winter
annuar precipitation
data series
in the pacific
Northwest
for the
sample period
a-year
do not change significantly
with
a
larger
sample
and
general,
are,
in
normally
distributed.
sampre statistics
derived
from the period
L94g-L979
are
very
relj-able
estimates
population
of
statistics.
summer precipitation
positively
series
are
sker./ed throughout
the Pacific
Northwest
with higher
values
west of the Cascades.
Mean and Coefficient
of
Variation
Perceptions
of rainfall
for most people begin and end
with
the mean or "normal"
amount and it
is certainly
the
most basic descriptive
statistic
to be carculated
frorn a
data series.
However, for the study of water resources it
is,
in
itself,
an inadequate
characterization
data.
of
Equally
irnportant
is the variability
about the mean.
The
(Cv) is the best and most stable
coeffi.cient
of variation
measure of the variabirity
of precipitation
over time and
has become the preferred
technique
for
depicting
spatial
patterns:
among others,
it has been used by Longley (L952)
in
the Canadian prairies,
(tgl6c)
Bradley
in
the
Rocky
Mountains, and Brazel and Ziriax
(tgZg) in central Arizona.
The coefficient
tic
defined
as the
mean:
of variation
ratio
of the
C v =+
X
36
is a dimensionress
standard deviation
statisto the
(4)
Table 4:
Comparative Frequency Distr ibution
for Two Sam.ple Peri.ods
Statistics
(data in inches)
Heppner, Oregon
4g years
x
Winter
Summer
Year
Winter
Summer
Y e ar
9.45
4.35
13.80
9.27
4.r4
13.41
s
(f940-f979)
S
k
-g.gl
A. 6 4
g.g8
2.49
L.69
2.69
91 years
(I889-1979)
2.03
1.59
2.6L
A. 2 3
9.65
A.32
4A years
(L940-L979)
lvlax
r5.13
9.65
2A.63
15.13
9.6s
20.63
ryrq
3.86
1.36
9.26
3.86
L.3g
I .24
Newport, Oregon
Winter
Summer
Year
s9.96
10.35
70"3r
-A.LL
L.g5
0.11
13"44
3.95
13.5r
89"3r
23.53
99.L4
26.7 fi
3.56
42.76
88 years (I892-L979)
Winte r
Summer
Y e ar
57.79
L g. 4 9
68.11
12.53
3 . 7g
12.85
A. 9 5
0.69
0.Il
37
8 9 .3 1
23.53
99.14
26.79
3"5A
37.72
It is preferred
over the standard deviation
which generally
increases
or decreases with the mean.
For example, a three
inch
standard
(mean annual
deviation
at
Forest
Grove
= 44.63 inches) in the Willamette
precipitation
Valley would
imply
only
small
relative
variability,
whereas the same
three
inch standard deviation
in a drier
location
such as
Malheur Refuge HDQ (mean annual precipitation
= 9;28 inches)
would imply
a very
large
value
of, relative
variabi}ity.
Division
by the mean, in effect,
normalizes
the standard
deviation
making it
comparable between areas of dif fere.nt
mean values.
The coeffj-cient
of variation
thus suggests the depend"ability
of
normal rainfall
may be
whether
a station
expected to receive essentially
the same amount each year or
if
the interannual
variation
is great.
Brazel and Ziriax
(1979) have determined that a
T-year sample is sufficient
to estabtr-ish a stable value for the stati-stic.
For other
time periods
absolute values may vary but the spatiat
pattern remains essentially
the same.
Means and coefficients
of
variation
are
included
in
the basic
data
tables
of
Appendix B and their
spatial
distribution
in
is analyzed
Chapter IV.
Percentiles
A common method for assessing
the likelihood
of certain
rainfal-l
amounts,
a method independent
of
the
form of the
frequency
distribution,
is the identification
of percentiles
positional
measures
derived
directly
from
the
ordered
data.
median
The
is
the
middle
value
the
ordered
of
(the
observations
percentile).
s0th
our
sample of
4g
In
items
the median is defined
as the average
of the
2frth and
items.
21st
As earlier
illustrated,
to
the mean is equal
the
median
in
a
normally
distributed
a
sample.
In
positively
skewed distribution
the
the median
than
is
less
mean.
There has developed
a preference
among climatologists
for
the
median
as
the
basic
arid-zone
statistic
of
precipitation
because
the mean value
an unrealisimplies
tically
high level
of expectation.
The data series
can be divided
number
into
an arbitrary
of equal parts
symmetri-cal
about the median.
is usual to
It
divide
the
sample
into
parts,
ten
and
or
four
deciles
quartiles.
Deciles
divide
the sample j.nto equal parts
of LA
percent
each,
the quartiles
parts
into
equal
of 25 percent
eaeh.
The first
decile
is the amount of precipitation
not
exceeded by the lowest
10 percent
of the values,
the second
decile
is the amount not exceeded by the
lowest
2g percent
of the values
and so on.
quartile
first
is
Similarly,
the
the
amount not .exceeded by 25 percent
the values.
of
The
(equivalent
quartile
second
is
the
to
the
fifth
decite)
med j-an.
The
basic
data
tables
i-nclude
in
Appendix
B
38
values of the firsr
(L0 percent and 9g
and ninth declles
percent) and the first,
quartiles
(25
second and third
percent, median, 75 percent).
In Figure 11 is a graphical
represent,ation
percent,ile
of
monthly
values
at
two
W a s h i n g t o n s t a t i o n s , A b e r d e e n a n d Y a k i m a W S OA p .
An interesting
application
of percentiles in climatological analysis is a study of Australian drought by Gibbs
and Maher (L967) in which rhey demonstrated that, the first
deci le
range on annual maps for
the per iod
1885-1965
corresponds well with Australian
droughts as recorded by
Foley (1957). Further useful informaLion can be obrained
from
these
data
with
inrerquartite
(75rh
the
range
percentile
25th percentile)
and the interdecile
range
(90th percentile
10t.h percentile).
is
The latter
particularly
useful for documenting extreme conditions.
Users
of
these
data
should
the
.
be
avrare that
percentile values here presented are descriptive statistics
rather than inferential;
that is, they are not appropriate
for prediction
in the strict
stat.istical
sense.
However,
if we base our estimate of the climatological. future on the
record of the past, these data do have predictive
value.
They
do
at
least
help
ro
del imit
rhe
range
of
possibilities.
I N F E R E N T I A LS T A T I S T I C S
Inferential
statistics,
in contrast to descriptive,
are involved whenever the question of probability
arises.
A precipitation
data series as developed in this study is
necessarily
a
sample extracEed
from
a
much larger
population of events.
Inferential
statistics
allow one,
within strictly
defined limits,
to make statements about
the population based only on the sample data.
T\do forms of
analysis are discussed below,
Confidence Intervals
for
Mean precipitation
The
interpretation
given
of
a
for
mean
value
precipitation
depends on whether one uses the value as a
descriptive or as an inferential
statistic.
Essentialt y,
the mean as a descriptive
precisely represents
statistic
the
sample considered;
for
example, the
mean annual
precipitation
at Ashland for rhe period Ig4A ro I979 was
I9.51 inches.
However, the use of t.his sample mean to
estimate the popuration mean is an example of statistical
inference.
There is a temptation to allow the mean to slip
from the category of descriptive stat,istics to the category
of
inferential
predictive
or
statistics.
is
Thus it
appropriate to present some quantitative
estimates of the
39
PERCENTILEVALUES
M O N T H L YP R E C I P I T A T I O N( I 9 4 O - I 9 7 9 )
t 2 0
*
t8
90%
to
."1-lsy.
l4
t
t
f
Nl2
r C
--
i
%
*
\l(
\
A
, !ra
l
i
-A
'.
,40/^
S
/
8
*-
{
,.
i
o
|ff/"
I.'
,
4
1
2
o b
rJ
F
9465
3.O
I
l
A
MONTH
M
.
J
YAKIMA WSO AP
2.A
2.6
2.4
,.
2.2
{
2.O
90%
, l '. t
;r.6
"t
5 '. o
*.
1.2
t.o
r5OY"-tt
4.8
4.6
o.4
- 2 5 % -* - '
/
...*
o.2
o.o
Figure
L94A-I979.
*
1A7" *
N
HONTH
11.
Annual Progression
Data in Inches.
40
of
Monthly
Percentile
Values,
reliability
of the mean precipiration
amounts listed in the
basic
data
table
purpose a
of
Appendix B.
For this
two-tailed
studentt s t-test
is
used to construct
a 95
statement for the AT-year mean.
Percent confidence interval
The format for this statement for a t-distribution
with 39
degrees of freedom is:
x + 2.02
fr
where s is the standard deviation
a n d n = 4A (sample size)
Substituting
i
the mean annual precipitation
-
(s)
1
of the sample
at Ashland:
19.51 inches + 1.57 inchesr.
which says that, the population
(long-terrn) mean estimated
from our AA-year sample will
lie in the range 17.94 inches
to 2L.A8 inches.
In other brords, if random samples of size
46 are taken from the entire population only five percent
of aIl
samples wilI
have such extreme values of
and s
that
they give a mean value outside
of
19.5f !
I,5Z
inches.
An increase in sample size would lead to a decrease in
the width of Ehe confidence interval.
The width of the
interval
as a percentage of the mean will
generally be
larger in drier areas in which che relative variability
is
greater.
Because the mean is the primary statistic
of a
precipitation
series,
confidence
have been
intervals
cal-culated for seasonaL and annual varues for all network
stations and are included in Appendix D.
It
should
be noted
that
the
assumptions
one of
underlying this procedure is that the data be drawn from a
normally distributed
population.
However. other similar
studies (e.9. ltcDonald 1956, Brazer and ziriax
Lg79) have
shown that
the effects
of
non-normality
are not very
disturbing.
Also, as shown previously,
winter and annual
rainfall
series in the pacific Northwest are uniformly near
normal and even summerseries do not deviate as much from
normal ity
as
they
do
in
cl imatic
regions.
other
Neverthel-ess, the tabulated confidence intervals
should be
viewed as only good approximate measures of the reliability
of the mean.
Similarly,
a confidence interval. can be constructed
about the coefficienr
of variation.
rt, is sufficient
to
assume that values are accurate within an interval
of plus
or minus I0 percent of the calculated value.
4l
A second example of the use of statistical
inference is
the
determination
of
the
probabi I i ty
of
o
c
c
urrence of
v a r i o u s a m o u n t s _o f p r e c i p i t a i i o n
during a month, season or
vJater year.
Estimates of
this
t y p- e a r e o f
particular
importance
to
those
involved
in
the
management and
utilization
of water resources.
For this purpose knowledge of the form
of the frequency
distribution
is
critical.
Given
a
normal
frequency
distribution,
che area under the curve can be taken
to
represent the probabilities
of
mean,
and
about
99.7
deviations of the mean.
tion above and below tne mean,
'o standard deviations
of the
percent
within
three
standard
Precipitation
data from Newport and Heppner, presented
earLier
in
Table 4,
can be used to
illustrate.
trn
aPproximagely two-thirds of the years
Newport will
r
e
c
e
i
v
e
b e t w e e n 4 6- s 2 a n d 7 3 . 4 0 i n c h e s o f
winter precipitation;
Heppner will receive between 7.gs and
11.g5 inches of winter
precipitation;
and so on.
carcuration
of values at any
probabitity
level can be done by rabularing tne aila
under a
normal curve, a standard tabla
found in most, stat,istical
r efe rences.
However it is often easier and more useful
'o work with
the cumularive f.requency distriouii;;:
For rhis rechnique
we use arirhmeric
(normal) probability
paper which has a
vertical
scale designed so Ehat the cumulative
frequency
curve of a normal distribution
pl0ts as a straight
lin6r
calculated
varues
probabil ity
of
are
pl0tred
a
g
ainst
rainfall
values, using rh; formula
iouttn" and Leopold 197g):
F i =
x L00*
(6)
the
_p e r c e n t a g e f r e q u e n c y o f
: years with a riinfaff
amounr
:icular rainfall
having rank m
.tude.
The percentage of past
ability
(a1so in percenr)- of
_ltormalprobabi.liry ploEs of seasonal data are presented
ror Newport and Heppner (Figure
12).
Winter precipitation
values at Newport deviage -on1y sl ightly
from a srraight
42
Figure
Norma1 Probability
Plots
of
L2.
Seasonal er ecipitation
NewPort,
Oregon ( L94CI- r e7e)
Heppner,
Oregon ( L94s- Le7el
( L892- r e79l
( L89s- Le7e)
:
E.
E
G
o
ED
o
o
co
e
)
{,
q
e
z
g
o
o
o
o;
s
a;
.'*
p
o
ll
o
L
a
o
E
o
z
(>
o.
o
t
oa
tr
o
0
CL
v
o
+
F
o
E
3
44
q
I
6
o.
cl
o.
@
=
c
o
o
.=
.s
o
4
o
E
E
f
an
ra.
o
q
o
(D
6
6
o
i
o|
c
;9
o
._o
lJ
o
c
o
E
E
a
a
o
o
o.
o.
o
o.
@
c
E E
$
b
o
c
=oo
.=
o,
c,
I
o
o
CD
4
o
o
o
c
;
o
c,
CL
CL
I
a::
t
r
o
o
o>
\
=
-o
o
II
o
G
r
-
o
I
E
i
zo
,
Q
6
(o o r? D
o
o
i
o.
=
.9
o
.s
o
4
o
?
t
r
o
g
)
--
o
D
saqlul
N
u
l
g
)
:
q
I
O!
6
o
o\
o
c
.9
o
:4
I
o
A.
ID
E
E
t
v,
sl
o
o
o
o;
o
?
-
q
-
o
l
.
h
@
u
N
r
l9qJUl
47
g
@
N
?
(
o
'
indicating
the near-normal frequency distribut.ion.
1ine,
in
The calculated straight, line smooths any irregularities
to
equivaLent
50 Percent
the
and
the
mean is
data
probability.
If it has been determined that the data series
it
is not necessary to
approximates a normal distribution,
p
o
i
n
t
s
fot example the
plot all points.
s
u
f
f
i
c
i
e
n
t,
a
r
e
Two
mean (59 percent) and the mean + one standard deviaEion (16
and 84 percent).
line can be used to
Once constructed, the probability
p
r
e
c
i
p
i
t
a
t
i
o
n
above or below
p
r
o
b
a
b
i
l
i
t
y
o
f
determine the
any vaLue. At Newport, for example, there is a 2g Percent
wilI
be approximately 48
chance that winter precipitation
that winter
inches or less and a 46 Percent probability
S u m m e rd a t a a t
precipitation
will
be 56 inches or Iess.
the normal line as closely as do winter
Newport do not fit
and 9g percent
data.
Ilowever, between che IA percent
The
accurate.
probability
i
s
s
u
f
f
i
c
i
e
n
t
l
y
f
i
t
levels the
w
i
n
ter
y
i
e
l
d
f
o
r
f
i
t
a
c
l
o
s
e
data series for Heppner also
s
u
m
mer
f
o
r
p
e
r
c
e
n
t
a
n
d
IA
9g Percent
values and within
v a Lu e s .
Similar probability
Plots based on a 9T-year record are
can be seen that predicted
offered for comParison and it
values assessed from the 4A-year record are nearly identical
In general, the shorter
to those from the longer record.
record tends to overestimate the amount at any probabillty
are moderately
1eve1. For data series whose distributions
it
is often Possible Eo
direction
skewed in a positive
by
frequency distribution
modify the shape of the original
t
h
e
commonly with
var iables,
transforming
the or ig inal
f
o
r
Fortunately,
square root or natural tog of t,he data.
the data in this study, even with a positive skew, results
LA
within
val id
certainly
are
non-transformed data
of
percent and 96 percent levels.
48
IV.
S P A T I A T P A T T E R N SO F P R E C I P I T A T I O N
The data compiled, processed and presented in tabular
form in chapter rrr allow a wide range of possibilities
for
interpretation
and use by
researchers
and by
water
m a n a g er s .
In
this
chapter
presentecl
the
data
are
cartographically
in rhree different
formats, all of which
permit
further
insight
into
the
complex nature
of
precipitation
variabit ity
in the pacific
North$resr.
The
presentation
first
is based on a set of
isopleth
maps
depict.ing means and coefficients
of variation
for months,
seasons and the water year.
Next, is a series of profires
which illustrate
the annual progression of monthly values
of the mean and coefficient
of variation
individual
at
stations.
Third
is
an
analysis
of
interstation
correlations
of monthly and seasonal precipitation
with t.he
results sunmarLzedon a set of isocorr maps.
},TEANS
AND VARIABILITY
The two stat,istical
characteristics
that, best i11ustrate the spatial
and temporal variation
of precipitation
in a region are the mean and the variability
about the
mean.
This section is a discussion of the relationship
between mean amounts and
interannuar
variability
as
expressed by the coefficient
(cv).
of variation
These
statistics
for four key months and for winter,
sumner and
annual varues vrere mapped on a base of regional- topography
and are present,ed in tandem for ready comparison (Figure
13).
A map of
the
seasonal distribution
of
annual
expressed as the percentage occurring in the
Precipitation,
winter,
follows
(Figure l4) .
The mapi are intended to
represent
only
the broadscale aspects of
precipitation
distribution
in
the pacific
Norrhwest and nor detailed
areas.
Patterns for particular
The discussion Ehat folrows
is based prirnarily on Trewartha (l9gl).
Effects of the three dominant climatic controls in the
Pacific
Northwest
latitude,
topography and continental
versus marine influence
are readily apparent in the map
series.
The combined influences of latit.ude and proximity
to t,he Pacific
ocean are best illustrated
in the coastal
margin.
rnland across the pacific
Northwest the marine
i n f l u e n c e r . r a n e sa s t h e c o n t i n e n t a l
inf luence increases.
At,
the
same time
patterns
are
modified
considerably
by
topography from west to east.
while latitude
remains an
important control
throughout the region its
influence
is
much less apparent to the east., specificarly
in the rarge
interior
region east of the Cascades.
49
Figure
13.
Map Series of Pacific
Northw,est Precipitation
Statistics
(L94A-I979)
Mean and Coefficient
of Variation:
a) Annual
(Water Year)
b)
(October
l{inter
- Aprif
)
c ) Summer ( ltay - September )
d)
October
e ) ilanuary
f)
APril
g) JulY
50
-,
|
/--'--
c
o
+,
(t
-,r'----\
f
L
Jo
rF
o
+J
c
o
(J
rts
Its
(u
o
c)
E,
lrJ
E
lrJ
F
=
J
z.
z.
.o
@e.
c
.o
(u
=
i:;
{t!"
,rg
sew
,#&%
=\!/--
5l
g
o
+'
(o
I
ct
Its
o
+,
E
(|J
(J
(F
lF
(u
o
(J
d.
lrj
F
z.
=
-o
- \ . / '
't {||i-i
PE
(tt
(u
=
52
E
o
+,
(o
r-
.U
(+o
+,
g
(U
(J
lF
(F
(u
o
(J
&.
lrJ
=
=
V>
w
c
o
{J
(o
!
ro
(ts
o
+)
g
(u
(J
(F
lF
(I)
o
(J
d
lrJ
dt
O
F
(J
o
^i
E '
'o
OJ
/'-'
=
54
g
o
+,
nt
!(tt
lF
o
+,
c
(u
I
(F
q-
(u
o
(J
d.
z,
D
(u
g
(o
(t,
=
55
E
o
+)
|o
L
{o
rF
o
P
(u
o
l+
(F
(U
o
c)
c
o
+,
(o
!
G'
(F
o
+J
(u
(J
(F
rF
o
o
(J
J
D
g)
g
'o
(u
=
57
Figure 14. Winter Season precj-pitation
Expressed a s a
Percentage of Annual Precipitation,
Data in
L94A-L979.
Inches.
58
The infruence
by Trewartlra (t9gt,
of topograptry
'
p. zbli t
is
perhaps
best
summarized
The North American west,
situated
between the
Rocky Mountains
pacific
and the
Ocean,
i"
indeed
a region
of
precipitation
complexity
both
as
regards
mean annual
amounts
and
seasonar
distributions.
More than
in other
parts
of
the
country
the
west's
terrain
features,
expressed
in
both
artitude
and
directio_nal
alignment,
play an important
role
in
inf lu.encing
the
lpatiat
ana
temporal
distribution
of rainfalI.
The cascade Range is obviousry
the dominant terrain
feature
in the Northwesl,
indeed one bf the most striking
crimatic
divides
in the worrd.
rt effectively
separates the area
into
two fairly
distinct
climatic
iegions,
east versus
west.
margin
precipitation
. _al"lg the coastar
amounts and
variability
*?y
be exp
rainid
i;
teims
-pacif
of
the
seasonar
migration
of the North
ic suntropicar
rrigrr.:
ana
of the
jet
stream and associated
cycronic
on its poreward
side.
M o s t o f t h e a n n u a l p r e c i p i t a "t it o. onr,^ "
from g4 to gA
percent,
occurs during the winter season.
In fact most of
western oregon and washington receives more
than go percent
of
annuar
precipitatio-n
in
winter.
This
maritime
precipitation
pattern
of the North pacific
coast is the
most important
and extensive
producei
of precipitation
in
the west.
Tl" rainy season exLends from september to
M
a
y,
thereby overlapping
into our ,,summer', season.
These rains
originate
in
midratitude
disturbances
which in turn are assoliated
with a widery fluctuating
jet
stream and wi_th rarge
synoptic
trough
patterns
i
n
t
he
atmosphere.
seasonal
expanJion
and contracti_on
o
f
t
h
e
circumporar
vortex
creates
a
distinct
n
o
r
t
h
t
o
s
o
u
t
h
gradient
of mean amounts and seasonar distribution.
with
higher ratitude
the rainy period is of ronger duration
and
seasonal
and annual
amounts are greater.
The highest
annual
and seasonal
amounts
occur
atong
the
northern
washington coast and resser
amounts occur with decreasing
latitude.
Departures from this pattein,
such as along the
southern
oregon coast,
probablf
result
from top-graphic
infruences The g"n"..i
north-to-south
gradient
arso
exists for monthly means.
The winter
concentration
of annuar precipitation
on
the southern oregon coast, armost
so fercent,
iJ as high as
anlrwhere in
tl"
country
and decreises
steadiry
to
the
north.
The /expranation is again in the rength of the
r
a
i
ny
season.
N,ear the california
border
it
is- generally
c
o
nfined
to
our designated
winter
months,
October through
Aprir;
to the north it often overraps
into rate and earry
s unrmer
59
Interannual
variability
of annual and winter
season
precipitation
in the coastal margin is essentially
uniform
from north
to
south,
the
entire
strip
responding
to
fluctuations
in the intensity
and frequency of midlatit.ude
storms.
However, individual months exhibit a north-to-south
gradient
in
coefficients
of variation--increasing
values
with decreasing latitude.
In other words, more variability
is found along the outer (lower latitude)
margins of the
circumpolar vorEex.
!-or the same reason coefficients
of
v a r i a t i o n i n t h e s u m m e re x h i b i t a s i m i l a r g r a d i e n t , r a n g i n g
from 26 percent at Neah Bay in the north to 44 percent at
osummer*
Gold Beach in
the
south.
Our definition
of
accounts for this as l{ay and september receive most of the
'summer" rainfall
in $restern Oregon and Washingt,on.
The lack of significant
summerprecipitation
is due to
the unusuaL poleward displacement along the coast of an arm
of
the North Paci fic
high and the cool
coastal
waters
associated
pattern.
with
this
As described
by patton
( 1 9 5 6 ), t h e n o r t h w a r d d i s p l a c e d a n r i c y c l o n e
is nor only
effective
in stabilizing
rhe air
but also acts to block
depressions
from regular
penetration
to
the
continent.
Farther
north
the
anticyclone
becomes weaker and more
variable in position
and disturbances bring increased vrarnr
season rainfall
to the coast.
I n l a n d t h e m a ri n e p a t t e r n i s s t i l l
dominant but. the
effects of topography modify the initial
partern of means
and variability.
North-to-south
gradients
not
aB
are
clearly defined.
Mean precipitation
over all
time periods
increases on windward slopes and extremely
high
annual
precipitation
totals
occur in
the Olympic t"lountains of
Washington and in the Oregon Coast Range.
On the lee side of the mountains a rainshadow exists,
as can be seen most dramatically
just east of the Olympic
Mount,ains.
To i llustrat,e,
Forks I
E on the west side
receives LL6.2g inches, mean annual precipitation;
Sequim,
60 miles to the east and on the lee side receives 15.97
inches,
precipitation.
mean annual
is
The rainshadow
pronounced in the Puget Sound area as far south as Tacoma.
It is an area of relatively
modest precipitation
and wintef
rainfall
contr ibutes
percentage
a
smaller
annual
to
totals--the
lowest west of the Cascades.
Farther sout,h the Iess cont,inuous nature o f the Coast
Range permits easier entrance of pacific
air
and allowg
increased precipitation
as far south as cot,tage Grove at Ghe
southern end of the Witlamette ValIey.
In th€ intefior
valleys of southwestern Oregon, in the lee of the highef
Klanath Mountains, precipitation
(for exam:
again declines
ple, Ashland 19.61 inches).
Although the inrerior
t
o
p
ography,
the percenr
by
precipitation
pattern 1s altered
in
of annual rainfall
occurring
60
gradient as
the winter shosts much the same north-to-south
in the coastal zone.
This is to be expected because of the
influence of the latitudinal
control, the percent of wint,er
concentration increasing southward.
is also altered
The pattern of interannual variability
of variation
in the lowland between
inland.
Coefficients
the coast ranges and the Cascades are not uniform from
north to south.
Stations on the east side of Puget Sound
have low vaLues, comparable Eo their coastal equivalents at
the same latitude.
Conversely, most of the stations in the
willanette
and southwestern
Oregon have higher
Valley
coefficients
of variation
than their coastal equivalents.
On the windward slopes of the Cascades mean precipitation
the
throughout
increases
and variability
remains low
north-south extent of the range.
Eastern Oregon and Washington are a part of the larger
by
type
descr ibed
Intermontane
Region,
a
c1imatic
n
t
a
i
n
s
to
T r e w a r t h a , w h i c h i s s i t u a t e d b e t w e e n t h e R o c k y I ' t' oc u
he
west.
to
the
east
and the
Cascades and Sierras
less
than
at' equivalent
Precipitation
is
everywhere
elevations in the Cascades and to t.he west.
Howeverr there
is a considerable range in annual amounts.
The vrettest
areas are in northeast Washington and the mountains of
northeast Oregon. The driest
region in the two states is
the Columbia Basin of south-central
Washington where mean
several
annual precipitation
is
below 8.AA inches at
stations.
The driest station in this netrrrork is Sunnyside
( 6 . 9 4 i n c h e s ).
are two-fold
Synoptic patterns causing precipitation
in contrast Eo the single dominant mechanism to the west.
in winter
are in response to
General widespread rains
midlatitude
storms which have a lower moisture content
after
crossing the western mountains.
Summer rains are
contribute
more local
and convective
in
but
nature
significantly
to annual totals.
Throughout the Interprecipitation
is
less
than
75
mountain Region winter
percent of the annual total,
less than in
considerably
testern Oregon and Washington.
As discussed in the next
section there is a distinct
late spring-early summer rainy
period in addition to the winter maximum.
There exists a suggestion of a north-to-south gradient
in annual and seasonal totals.
As explainedr cyclonic
control
is stronger and winter
rains more abundant with
it
is
increasing
latitude
and
not
along
the
coast
unexpected that the same is true east of the Cascades, with
higher values to the north.
However, most of the variation
in mean seasonal and annual precipitation
appears to be the
result of topography rather than latitude.
6l
spatial distribution
of seasonal and monthly precipitai
s
v
e
r
y
s
i
m
i
l
a
r
t
o
t
h
e
annual pattern, the iriest
areas
!i9n
being the columbia Basin and the rrigh desert of southeast
Oregon. Northeast Washington and. the mountains of northeast
Oregon have the highesr t6rals.
spatial
patterns
of
interannual
variability
for all
time periods reflect
closery the patterns of mean precipitation;
the areas of lower precipitation
grearer
exhibit
coefficients
of variation and vice versa.
rt is inteiesting
to note that,
in comparison with equivalent latitudes
wesL
of
the
cascades,
monthly
and
Jummer coefficients
of
variation
are definitety
higher but winter and annual values
are about equal to the rdestern area.
The coefficient
of variation
is an extremely informative statistic.
Although it
is a ',normalized" ieasure of
variability
it
is still
a function of the mean, making
spatial
comParisons difficult.
Additional
information can
be obtained by developing a regression relationship
between
the mean and the coefficient
or variation
and caiculating
residuals.
For annual daca che coefficient
of variation
decreases with increasing precipitation
to a value of about
56 inches, beyond which it
changes but little.
A curve
fitted
mathematically to rhe data yielded an expecred htgh
relationship
= 9.56).
(!t
Residuals from the regressiJn
hrere calculated and plotted for alr stations in the ietwork.
The same
;rrocedure was followed for $rinter 1r2 = 0.44) and
summet (8. = g.5I) data.
The maps of rhe residuars (Figure l5) highlighr
some
very int.eresting aspects of interannual varianirity
in the
Pacific
Northwest.
Residuals are interpreted
as forlows:
positive
values indicate coefficients
oi variation
higher
than expected for the mean precipitation,
i.e. high relallve
variability;
negative
values
indicate
low
relative
variability.
Residual values greater than +g.g2 or ress
than -9.92 are considered to be Lignificantly
different
than
zero and only regions of this magnitude are outtined.
Residuars for
a n n u a r p r e c i p- ict aa st icoand e s . r e v e a r
a rather
complex pattern
west
of
the
High
relative
variability
is apparenr in the sourhern willanierre va11ey
(e.9. Eugene wso Ap +0.o4) , rhrough the umpqua Rlver vallelr
and into the interior
valleys of southwesiern. oregon (e.g.
Grants Pass +a.95) . rn contrast,
the northern willamette
valley
and much of
the puget Lowland are areas of
low
relative
variability.
Low varues al.so prevail
in
the
coastal margin although in most cases absolute values are
not as large as in the puget sound area.
There appears to
be no correlation
with
latitude
nor
with
mean annuaL
prec i pi ta r ion .
62
Figure
15.
!4ap series
of Rerative
Variability
of seasonar and Annuar
Precipitation,
Expressed by Residuals
from the Regression
of Coefficient
of Variation
as a Function of Mean:
a) Annual
Note:
Areas 1o!ed
vari.ability,
Areas noted
variability,
b)
Winter
c)
Summer
(water
year)
as positive
are those with high rerative
residuar
great,er
values
than +g.g2.
as negative
are ttrose with row rerative
residual
values less than -9.62.
63
*.,--.....--/
-'
i------.
l
i
i
d.
lrl
d.
|lJ
F
=
J
q
z.
=
G'
L-
,
t
,'
t
,
-;.-ri
'
I
l
(
l
t
|i
i
l
I
i
,
(/
| /
r
."^._!
-
'
/
t
- l'
t----i.
l
t
l\ (i
\,
)
/
-/
,'
{l
r
i
f)
,
I
/
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r
,
,---'
('--l -\
--
r
'
l
t
,'/
(
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t
i
1
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I
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-l-
.a'\
I
!
I
...\._f..
l
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-
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t
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-
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-
(,
)
i
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,,'
t
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I
E
lrl
=
=
=
at1
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al '- \ i
,
Lffiq
(^r
l:)
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__-iL-.{
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t
-
ltr
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E
frJ
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z.
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("'az
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7
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l
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z..it
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(rjr!
z--
\.t
n J - z
5
65
\
\-/
l
z-\
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!
'-Il
:
l
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\_--- -\-/
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P-\\
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*-i
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|
East of the cascade divide the pattern is more distinct
and a dramatic contrast exists.
A broad strip including the
eastern flank of the range and adjacent areas
from canada to
northern california
h a s u n i f o r m l y h i g- tho r e r a t i v e v a r i a b i l i t y ,
residual values ranging from +A'.g3
+U.Ag.
Some of the
highest
values are found at stations
just
the
east of
columbia Gorge.
rn rhe norrh this regioi of hl-g; relative
variability
extends into
the western okanogan- Highlands
(e.9.- Nespelem 2 s +a.96) and in the
south it extends inta
south central oregon.
From north to south t,hroughout the eastern third of
the
Pacific
Northwesr
is
oroia
region
of
unifor.rnly low
relative variabitity,
residuar valuei ranging from -a.02 Eo
-g -95.
Three areas stand out on the arriual map:
the
eastern okanogan Highrands, the major portion of the
Blue
Mountains and southeast oregon incruafng
the snake River
Plain.
Absorute values of
these negative residuals
are
comparable to those of the inqerior
iowlands west of the
cascades and appreciably higher than those along Ehe coast.
seasonal
concentration
precipitation
of
partially
exprains the parrern of low relarivi
,ruriability
i; easqarn
oregon and washington.
Late spring and early Sumrnerrains
contribute
a significant
percentage to annual totals,
thus
there
are
essentially
iwo
seasons.
rairiy
Howev€fr a
correlation
between seasonal
and relat,ive
n -ec e nptar a
for
q it ifoi nc
y?: i?bi I i.y
rhe
resr
o f " or h
N
orrhwest ls
grrrlcult
to subsEantiate.
The distribution
of residuals
for the winter
season
differs
littre
from
the
annual
other
than
having
higher absolure values
as high as +6.r4
99n:istenrly
(Dallesporr FAA-Ap) jusr easr of rhe cotumbia
Gqrge.
The
dominanr area- of high relative
variabil iry i"
is in
s o u t h w e s t a n d s o u t . h - c e n t , r a l o r e g o n , f r o m - t h e " iRnoi igr u e R i v e r
Valley acress the cascades as far as Lakeview z wr'Il,i +0.g4),
t
rn summer, as exBected, there are greater deparEures
from
the
annuar
patiern.
Along the
eregon coast
ar@
positive
residuals,
indicating
ntgf, relative
var iabil ity.
values range as high as +a.rr
(dold Beach R.s.)
on rhe
southern oreggn coast.
At
the other
extreme is
tteah
Bay I Er washington, with a value of -a.a5.
other extensive
areas of high relative variability
are through rhe Klamath
Mountains
of
southwest
oregon
and
in
nortn
centrar
Washington east of the CaScadeJinto rhe OkanqganHighland$.
In the western parr
of
rhe ekanegan Hightinds
residual
v a l u e s a r e e x r r e n e ( e . g . N e s p e l e m2 { + g . l g t .
Extensive areas of
lqw relatiye
variabil ity
in the
summer are found in extreme northwest, washington from
the
coast, to the North cascades and also in the nirthern
ore.gon
CaFcades.
East of
th@ Cascades the area combining [fr.
66
lower columbia valley just. east of the gorge and t.he yakima
valley has rhe largest negative varuei
(E.g. Dufur -g.Ls
and Arl ington -9.16') in the paci f ic Northwest.
Easthrard
the extensive north-to-south
belt from the canadian border
through the eastern okanogan Highlands, along the eastern
edge or the Palouse Hills-, the eastern Blue lvlountains and
southward to the snake River ptain and the owyhee uplands
has negative values ranging from -9.02 xo -g.IA.
The discussions that follow in the remainder of this
chapter describe in more detail
precipitation
patterns in
the Pacific
Northwest but do nor exprain saCisfactorily
these observed patterns of relat.ive variability.
rt is an
interesting
problem that demands further study.
P R E C I P I T A T I O NR E G I O N S
preceeding
In
the
section
pat,terns
broad
of
precipitation
and its
interannual
variabitity
in
the
Pacific Northwest were described in terms of major crimatic
controls.
LocaI details are best considered in the context
o f h o m o g e n e o u sc l i m a t i c
regions; that is, distinct
geographic areas within which contrors interact so as to produce
Precipitaion similarities.
one of the primary purposes for
the identification
o f h o m o g e n e o u sr e g i o n s i s t o p e r m i t t h e
characteristics
at individual
stations to be interpreted as
more representative
of a larger
area,
thus being more
useful in the study of trends and cycles in the data.
Distinct
climatic
regions have not been adequately
defined for the Pacific Northwest although there has been
some interesting
work toward this
end.
sneva and calvin
(1978) developed an improved thiessen
grid
system for
eastern
precipitation
oregon
based
on
int,erstation
correlations.
!ti1ler er al (1973) devetoped relationships
between precipitation-frequency
values and climatologicll
and topographic factors at observing sites.
A favorite
approach among cl imatorogists
in recent
years has been principal
components analysis.
The obvious
value of the methodology is that it can be used to reduce
l a r g e a r r a y s o f d a t a t o d e l i n e a t , e h o m o g e n e o u sr e g i o n s a n d
t'o more ef f ectively
document changes over space and time.
severar interesting regional studies have been successfully
completed $rith this technique.
For example, precipitation
patterns
have been described
in
Nevada (sr,idd Lg67),
Arizona (Jotrnson r98g), sourheasr Ausrralia
(wrighr rg74)
and New ZeaLand (saringer l9B0).
(1969) used the
setlers
approach to determine precipitation
anomaly patterns for
the entire r^restern united states for each month and skaggs
( 1975) described rhe sparial
parrern
of drought in irre
American Midwest.
67
study attempts
In the course of this
have been made to
delineate
homogeneous regions in the Pacific
Northwest.
The
task is not yet accomplished to our satisfaction
and will
be
described
in another report.
for the discussion
Fortunately
that follotrs there exists
division
a natural
and logical
of
the
precipitation
Pacific
Northwest
into
regions
of
similarity
geomorphic
the
and
regions
of
Oregon
Washington (figure
t6) .
profiles
AnnuaI
and
of
monthly
mean precipitation
monthly coefficients
have been prepared for the
of variation
subset of 43 stations.
are grouped together,
These profiles
(in Figure Ig, beginning
by region
on page 84).
Trewartha
( fggf)
profiles
precipitation
used annual
to
typify
of
climates
throughout the world.
Here we consider the pacific
profiles
Northwest
in greater
detail
the
and include
of
coefficient
of variation.
ae
The study of these profiles
as those
well
from
other
answer many
stations
should
questions
concerning
the
distribution
of
spatial
precipitation
variability
in the Pacific
and its associated
Northwest
but it
also raises
that
require
many questions
mere examination.
that fsl-lows is in no way
The discussion
complete but is intended as background for subsequent work.
oI)rmpic
Mountaiqs
- Coast
Range
on the peninsula
Located
weet
of
Sound the
Puget
a compact elevated
structure,
Range is
Olympic
Mountain
heavily
glaciated
and maturely
dj-ssected with sharp ridges
and deep valleys.
from a few
The differences
in elevation,
hundred to almost 8,AAg feet,
and the great contrasts
in
precipitation
have produced a diverse pattern
of vegetatJ-on,
Thick stands of conifers
dominate the lower and intermediate
slopes but give way to areas of subalpine
vegetation
in the
higher
elevations.
The range of annual precipitation
ie
greater
here than for any region
in the Pacific
Northwest.
Western slopes receive very heavy precipitation,
as much ag
2AO inches in sone locales,
of the
while on the lee.side
mountains are areas with less than 2A inches per year, ttre
driest
of any Washington stations
west of the Cascades.
South of the Olympics ttre Coast Range extends to the
joins
vicinity
of Port Orford on the Oregon coast where it
the geologically
older Klamath Mountains.
Ttre range has a
relatively
primarily
simple
structure,
of
consisting
moderately upfolded marine sediments.
e
l
e
v
a
t
i
o
n
s
are
Summit
not impressive
although
there
rise
souLhwqrd
is a general
from the Chehalis River in Washington to elevatj-ons of 3,5nfi
feet adJacent to the Klamath Mountains.
Along the western
margins
in
the
range
from
the
Washington
is
separaled
Pacif ic
a
lowland
that
narro\irs
and become€
Ocean by
diseontinuous
in Oregon where the eoastline
is one of great
68
a
\8:
Yotino wSO AP
;ET-WILLAMETTE
LOWLAND
a
a
o
Hcppn. '
BTUE
MOUNTAINS a
Bolcr kCXl
o
Doyvilla
KTAMATH
MouNTArNs\ .."..,{o*"^r,
fledfo'd
WSO
"n
AP
a
a
Xlomoih
t
Fotls 2 SSw
BASINAND RANGE
lot.vicw
O
2 NNW
Figure 16.
Geomorphic Regions of the Pacific
Nor:thwest
( after
Ttrornbury 1965 and H i g h s m i t h
43-station
1973 ) with
Subset of Network.
69
between
contrast
headlands.
low
sandy
beaches
and
rugged
basaltic
To the east
the Coast Range descends to the Pugetto moistureas a barrier
Willamette
Lowland and stands
air masses from the Pacific.
Annual precipitation
bearing
on the higher
is abundant along the coast and even greater
(0S
western slopes (up to LsA inches) but declines abruptly
The combination
to 45 inches) in the lowland to the east.
ttre
of mild temperatures and adequate moisture has permitted
little
growth of dense coniferous
relatively
forests
with
from north to south or from the
composition
ctrange in forest
lowlands.
coast to the interior
a
is
the
of
Northwest
margin
Pacific
The coastal
b
y
m
o
d
e
r
a
t
e
characterized
typical
marine west coast climate,
heavy
latitude,
its
temperatures
with
a modest range for
For
and a high degree of cloudiness.
cyclonic precipitation
f
o
r
m
t
h
r
o
u
g
h
o
ut
the entire
coastal margin, and in a modified
t
h
r
e
e
a
t
l
e
a
s
t
all
of
western
Oregon and Washington,
(
T
r
e
w
a
r
t
h
a
are contmon
t98I):
features of precipitation
a.
b.
c.
maximum in the
single
there is a conspicuous
which occurs
annual profile
of precipitation
in winter;
a marked single minimum occurs in the sunmeri
and
a
is
maximum precipitation
the
of
month
function of latitude.
to
the
seasonal
related
aII
features
are
These
high as described
migration
subtropical
of the North Pacific
that North
in the previous
section"
Church (fgSa) believed
just
north
of the mouttr of the Columbia
Head WB station,
most closely
represents
a pure form of the coastal
River,
pattern;
orographic
precipitation
i.e.
one
without
in this data network
influence.
North Head $tas not included
in L962.
because the station
closed
However, the annual
profile
in Figure 18 with data
is included
of precipitation
for the period I93I-1960.
is the
characteristic
of this profile
The most striking
the
rnonth, and JuIy,
symmetry around December, the wettest
annualmean
the
stations
driest.
other
coastal
At
precipitation
is considerably
more than at North Head due to
and the
air
masses by highlands
the lifting
of maritime
At
latitude.
with
varies
character
of the annual profile
gtations
is
very
and northern
Washington
Oregon it
in
around December.
At Bandon 2 NNE and Brookings
synunetrical
profiles
Iess
are
on the
annual
southern
oregon coast
between mean
no difference
symmetrical
essentially
wittr
the
amounts for December and January.
This change reflects
maximum,
seasonal progression
of the monttr of precipitation
margin of Norttr
coastal
feature of the entire
a distinctive
70
America.
rt occurs later with decreasing latitude,
from
Anchorage, Alaska
(latitude
56oN, maximum rainfall
in
S e p t e m b e r ) ,- t o N o r t h e r n B a j a C a L i f o r n i a ( e . g . E n s e n a d a a t
latitude
32oN, maximumrainfall
in February).
Oregon and
washingron
(laritude
42o ro
4goN) farr
within
rhis
progression.
The shift
is related Eo the southward shift
paci f ic cyclone
of
the mean j et
stream and associated
track.
Annual profiles of variability
also exhibit a north to
south pattern in the coastal margin although they are more
erractic
and difficult
to explain.
on the washington and
northern Oregon coasts December, the vuett,est month, is also
the month of least interannual variability.
Such is not
the case on t,he southern oregon coast where March is the
least variable month even though four other winter months
are wetter.
The significance of March variability
is noted
also in northern washington. At Neah Bay I E and Forks I E
it is the second least variable month after December. yet
a t A b e r d e e n a n d A s t o r i a l r l s OA p A p r i l s t a n d s o u t o v e r I v t a r c h
as a month of surprisingly low variability.
This decrease
in coefficients
of
variation
in
the spring months is
difficult
to explain and requires further srudy of cyclonic
storm Patterns.
The
relationship
between
means
monthly
and
coeff ic ients
of
var iation
in
the
summer i s
more
predictable.
is
July
the driest
monrh throughout
rhe
coastal margin in response to the time of maximumstrength
and northward displacement of the North pacific
subcropical
high.
Variabil ity
is at a maximum in July and eugust.
High values of the coefficient of variation
in July are a
function of the extremely 1ow rainfall
toral-s but August
values are att.r ibutable,
in part,
to
the
intermittent
presence of weak f ront,al systems which may br ing rel-atively
large amounts of rainfalt
some years whereas August in
other years is completely dry.
Puget-Willamette
Lowland
The Puget-Willamette Lowland, the only large lowland
\,restof the cascades, is approximately 35a miles 10ng by 50
miles wide and ext.ends from the canadian boundary through
washington and into oregon as far south as cottage Grove.
rt
is a structural
trough downfolded between the major
anticl ines
of
the
coast
Range and the
cascades,
is
partially
firled
by sediments from the ranges and is an
area of low elevation and modesc relief.
The pugeE sound
area in the north differs
from the willamerte
valley in
thaE it has been glaciated.
An expression of this is the
irregular
form of puger sound which inundares a sizeable
area and by the cover ing of glacialty
deposited sands,
gravels and clays that has restricted crop agriculture
to
the recent alluvial
deposits of the river
valleys.
rn
71
of the Willamette
deposits
alluvial
the extensive
contrast,
for
suitable
area
provided
a much larger
have
Valley
d
ry
b
y
handicapped
are
areas
Both
farming.
intenlive
w
a
t
e
r
on irrigation
reliance
increasing
summers that require
r
a
n
g
e
s
.
mountain
snows of adjoining
provided by the melting
to the east of the olympics and Coast Ranges'
situated
annual
Lowland exhibit
the
Puget-Willamette
of
stations
to
similar
which are basically
profiles
of precipitation
o
f
t
y
p
e
The same strong annual
Jtations.
ttrose at coastal
w
e
L
t
e
s
t
apparent with December the
is immediately
variation
are
month ttrroughout and, as in the coastal margin, profiles
increasing
north.
However, the
to
the
more symmetrical
of topography can be seen in the fact that annual
influenle
profilesarenotasslrmmetricalasatcoastalstationsof
similar latitudes.
less than in
is considerably
Mean annual precipitation
margin,
in the coastal
or
side
on either
the mountains
latitudes.
equivalent
at
less
or
generally
one-half
part of the
in ttre northern
are greatest
nainshadow effects
lee. of the
t
h
e
t
o
i
m
m
e
d
i
a
t
e
t
y
a
r
e
a
.
S
t
a
t
i
o
n
s
Puget Sound
p
r
e
c
ipitation;
a
n
n
u
a
l
o
f
a
m
o
u
n
t
s
m
o
d
e
s
t
v
e
r
y
h
a
v
e
Olympics
a
n
d
S
equim (not
i
n
c
h
e
s
w
i
t
h
2
4
.
6
5
A
n
g
e
l
e
s
tor example, Port
Puget sound area is
The entire
shown) witfr L5.g7 inches.
o
f
T
acoma the lower and
s
o
u
t
h
b
u
t
r
a
i
n
f
a
l
l
one of reduced
the
m
o
untaine permits
c
o
a
s
t
a
l
t
h
e
o
f
n
a
t
u
r
e
less continuous
O
l
y
m
pia
t
h
e
f
r
o
m
P
a
c
i
f
i
c
.
a
i
r
m
a
r
i
n
e
o
f
freer
entrance
p
r
e
c
i
p
i
t
a
t
i
O
n
a
n
n
u
a
l
m
e
a
n
t
h
e
H
e
r
e
W S OA P i s i l l u s t r a t i v e .
of Wastringt'on
Seattle-Univ.
comPared to
is
49 .L4 inches
south
( 35.36 inches)
2N (34.32 inches) .
and Bellingham
a
m
o
u
n
t
s of
l
o
w
e
r
s
t
i
g
h
t
l
y
V
a
I
I
e
y
t
h
e
W
i
l
l
a
m
e
t
t
e
through
t
o
O
l
y
mpia
i
n
c
o
m
p
a
r
i
s
o
n
r
e
c
o
r
d
e
d
a
r
e
p
r
e
c
i
p
i
t
a
t
i
o
n
.rrt,r"I
m
o
u
n
t
a
i
n
s
.
c
o
a
s
t
a
l
h
i
g
h
e
r
t
h
e
o
f
W S OA P b e c a u s e
the
in
gradient
a north-to-south
also
There exists
t
he
l
a
t
i
t
u
'
i
l
e
d
e
c
r
e
a
s
i
n
g
p
r
o
f
i
l
e
s
.
W
i
t
h
a
n
n
u
a
l
o
f
amplitude
stunmef
months and dry
between the wet winter
difference
comparison can be
An interesting
months becomes greater.
(
l
a
t
i
t
u
d
e
and
49oN)
2
N
B
e
l
l
i
n
g
h
a
m
between
made
(
l
a
t
i
t
u
d
e
2N
B
e
t
l
i
n
g
h
a
m
e
4
.
5
o
U
)
.
U
n
i
v
.
Corvallis-State
o
f
m
o
n
t
h
s
w
e
t
t
e
s
t
t
h
r
e
e
i
n
t
h
e
i
n
c
t
r
e
s
receives
13.56
j-est
d
r
t
h
r
e
e
t
h
e
i
n
i
n
c
t
r
e
s
4
.
2
3
November-December-January,
Corvallis-State.
In contrast,
months of June-July-August.
months and only
w
i
n
t
e
r
t
h
e
t
h
r
e
e
i
n
i
n
c
h
e
s
Univ. has 2g.g5
m
o
n
t
h
s
.
t
h
r
e
e
s
u
m
m
e
r
t
h
e
2.2L inches in
for
of variation
The annual progression of coefficients
p
u
g
e
t
W
i
l
l
a
m
e
t
t
e
i
d
e
n
t
i
c
a
l
a
l
m
o
s
t
i
s
L
o
w
l
a
n
d
in the
stations
i
n
t
e
r
a
n
n
u
a
l
a
s
s
o
p
r
e
d
i
c
t
a
b
l
y
a
n
d
region
to the coastal
t
h
e
i
n
f
l
u
c
t
u
a
t
i
o
n
s
.
i
n
t
e
r
a
n
n
u
a
l
t
h
e
same
variation
is due to
t
h
e
T
o
g
e
n
e
r
a
l
c
i
r
c
u
l
a
t
i
o
n
,
t
h
e
of
features
controlling
w
h
i
l
e
m
o
n
t
h
v
a
r
i
a
b
l
e
l
e
a
s
t
t
h
e
d
e
c
i
d
e
d
l
y
north December is
the wetter
among all
is more consistency
in Oregon there
variation
o
f
f
i
c
i
e
n
t
c
o
e
f
t
h
e
v
a
l
u
e
s
o
f
winter months.
L,ow
noted on
a
f
e
a
t
u
r
e
A
p
r
i
l
,
o
f
a
n
d
Mareh
in the spring moRths
72
the coast, is also apparent here.
months of greatest variability.
JuIy
and August are
t,he
Klamath l{ountains
Located in the southwest corner of Oregon, the Klamath
Ivlountains adjoin
the coast Range to the north
and the
cascades to the east.
They can be distinguished from the
other two mountain ranges by their
older rocks, a more
complex georogic history and their greater dissection.
The
Klamaths are composed of structures
of old
igneous and
metamorphosed materials
that
have been severely eroded,
resulting
in
high
sharp r idge crests
and deep narrow
val1eys.
Summit levels
have a general
similarit.y
of
e l e v a t i o n r V € l r y i n g f r o m 3 r O g A x o Sr O O 0 f e e E , w h i l e a b o v e
them are higher peaks rising to almost grTg0 feet.
Annual precipitation
in the mountains varies frorn 3a
to 96 inches and the slopes are largery forest
covered.
But the Klamath t'lountains are higher than the coast ranges
(with the exceprion of the olympics) and thus the sourhern
oregon valreys
such as that of the Rogue River receive
considerabry Less annual precipitation
than the willamette
Valley; for exarnple, Ashland (mean annual precipitation
=
19.61 inches) and t'ledford WSOAp (19.97 inches).
In rhe
ratitude of southern oregon the effects of the pacific high
are stronger so lower rainfall
amounts are not unexpected.
Although mean annual precipitation
is
modest t.he
annual profiles
are st.ill
typical of the marine west coast
pattern
with
December the $rettest month and July
the
driest.
However, some aspects of these profiles
suggest a
stronger
continental
influence
than experienced in
the
Puget-willamette Lowland.
For example, Ashland receives a
larger percentage of annual precipitation
in the spring as
compared to
Brookings,
a coastal
station
at
the
same
latit.ude.
This tendency toward a secondary maximum in the
spring is a characteristic
of much of eastern oregon where
the continental influence is strong.
puget,C o e ff i c i e n t s
of
var iation
are,
as in
the
willamette Lowland, much the same as at coastal stations aE
similar
latitudes.
D e c e m b e r,
the
vrettest
monEh, i s
certainly not the least variablei at Ashland, February is
least variable and at lvledford wso Ap it is January.
This
is
the same absence of
relationship
between mean and
coefficient of variation noted at stations on the southern
Oregon coast.
73
Cascade Range
of the Cascades extends
The Pacific
Northwest portion
a
for
from Canada to California
and separates
5gg miles
In
mild,
moist western climate
from a cooler,
east.
drier
that has
Washington the range is a broad uplifted
structure
glaciers
been deeply
and rapidly
eroded by Pleistocene
narrow
flowing
streams.
The Oregon Cascades are relatively
and
in east-west
extent,
have not been as severely glaciated
have much more volcanic
older
rock in the structure
with
younger
and
flows
Iava
exposed
flanks
and
along
the
are
fragments
there
along
the
crest.
White
strewn
differences
in geologic
structure,
size and rock type the
of
entire
length of ttre Cascades is surmounted by a string
from Mt. Baker
highr foung and potentially
active volcanoes,
in the north to Mt. Mcloughlin
in southern Oregon.
the
than the coast ranges,
Being considerably
higher
to marine air masses and
Cascades present a major barrier
particularly
are a region of heavy precipitation,
along the
a
mounts of
western slopes.
e
f
f
e
c
t
c
a
u
s
e
s
h
i
g
h
A "spillover"
precipitation
also on the upper eastern
flanks.
Although
precipitation
generally
range
the
is
heavy
throughout
and
greatly
amounts vary
d
i
f
f
e
r
e
n
c
e
s
i
n
e
l
e
v
a
t
i
o
n
with
g
r
o
w
t
h
of
p
r
e
c
i
p
i
t
a
t
i
o
n
exposure.
t
h
e
h
e
a
v
y
s
u
p
p
o
r
t
s
The
v
a
r
y
as
coniferous
forests
m
o
s
t
r
a
n
g
e
.
over
of the
Species
t^rith increased
on
temperatures
are
modif ied
elevation
western slopes and as precipitation
lessens with decreased
elevations
t
h
e
and on the
on
lee slopes.
Along the crest
areas
higher slopes of the major volcanoes are discontinuous
a
t
u
ndra
that
extend
above
timber
line
and
exhibit
vegetation
p
e
r
m
a
n
e
n
t
a
n
d
s
n
o
h
t.
complex up to areas of
ice
annual
values
and
of
monthly,
seasonal
High
precipitation
are due
on the western
side
of the
Cascades
not only
but to the
to the lifting
effects
of the highlands
p
r
o
g
r
e
s
s
fact
cyclonic
that
the
mountains
delay
the
of
storms thereby
increasing
the duration
of rainfall.
Much of
as sno\d and
the precipitation
at higher
elevations
occurs
accumulations
are among the greatest
in the United
States.
were
fact,
during
inches
of
snowfall
In
WY I972,
I122.9
=
(elevatiotl
recorded
at
Rainier-Paradise
Ranger
Station
the
in
feet),
recorded
the
largest
snowfall
ever
5,427
(Brennan f981).
United States
to
precipitation
amounts are
difficult
Unfortunatelyr
term
determine
for
since
long
many areas
in
the
Cascades
short
greatly
stations
are
few and totals
within
may vary
distances
as elevations
For the most
and exposures
change.
in
part,
and
elevations
stations
are
located
at
lower
relatively
protected
stations
valley
well
sites.
Of the
illustrated
for this
region,
Mazama 6 SE and
Lake Wenatchee,
(tietort
are
ttre others
Rimrock
Dam) are east of the crest;
on the wet western
flanks.
are
not
completely
Even these
representative
received
of the high amounta of precipitation
74
alny season begins earlier
at
in the northern Cascades have
precipitation
in the falI
and
:tween Diablo Dam, Washingron,
egon, will illustrate.
These
nean annual precipitation
and
March-June
Diablo Dam
I'lcKenzieBridge R.S.
3 9 . 93 i n .
3I.A2 in
16.05 in.
18.69 in.
Ear1.y season precipitat
!r Ln _e
northern station,
but
greater at Lhe southern
st€
systems but
the
r-ate season pattern
Trewartha (1991, p. 30L) explains,
"'
ri sD
rl ee soss
c1ear.
The seasonal shifr
of the jet polewar.d in spring
and summer does not seem
to occur in a
manner as in the southward
m o v e m e n t i n t h e" i " fuao1y1
and winter,
but instead one
iei- appears to rdane
in
the
south
in
late
win-ter whi 1e another
develops near the Arctic Circie.
ar north-to_south pattern
in
efficients
of variition.
In
9fV rhe LeasL variable monch
1 profile is small. Ar Diablo
75
Dam the coefficient
of variation
in JuIy is g.6A and in
August is 9.65, only slightly
more than the 9.53 in January
and
in
A.56
February.
the
With
decreasing
latitude
coefficient
of variation
in December, ttre wettest
month,
increases and the amplitude of the profile
increases.
Note
the relatively
high values in JuIy and August for the more
southern stations.
Annual profiles
of precipitation
and coefficients
of
variation
for the stations
on the east slope are essentially
the
same as those
on the west,
other
than
the
obvious
decrease
precipitation
in
totals.
is
the
An exception
slight
tendency for a secondary maximum of precipitation
in
May and June at Mazama 6 SE.
typical
This feature,
of much
of eastern Oregon and Washington, will
be discussed later.
The Cascade Range serves as a transition
between the
climate
to the east and that to the west.
For the western
region
as a whole the annual progression
of monthly means
and coefficients
of
variation
is
best
expressed in
the
coastal margin where differences
can be clearly
explained in
terms
of
latitude.
profil"es
Annual
are
modif,ied
only
slightly
from the coast to the Cascade Range by the complex
influences
of topography.
East of the Cascades modifications
from the initial
pattern
become more profound.
An exeellent
introduction
to
the climate of, th€ Pacific
Norttrwest east of the Cascadee ie
given by Trewartha (rgarr p. 3a5) in his description
of th€
larger
Intermontane Region:
Situated
as it
is between the Rocky Mountains
to the east and the pacific
Coast Mountains to the
west, this extensive
Intermontane Region is in the
rainshadow
of
hj-ghlands.
at
higlrer
Except
elevations
it
is,
therefore,
a region of modest
precipitation,
much of
it
bej-ng classif,ied
aa
steppe
or
semiarid,
although
are
some parts
generally
arid and others,
chiefly
in the north or
at higher elevations,
subhumid.
A dominant feature of annual precipitation
profiles
is
the
biannual
variation.
during
the
One maximum occurs
pacif ic
trrinter
season,
coincident
with
rest
the
the
of
Northwest,
and a second during
it
the rrtarm season although
is quite variable
in time of occurrence.
The Intermontane
Region thus represents
a transition
between the area of
strong winter maximum of the pacific
coastal
regions and the
marked
sunmer maximum typical
great
of
the
continental
interior
east of the Rocky Mountains.
in
Local variations
total
amounts of precipitation
and in the annual profileo
of
precipitation
and coefficients
of variatisn
are due to the
interaction
of
latitude,
relief
and distance
from the
Cascades.
regions
Eastern
of
th€ Facific
are
Northwest
dlecuseeel below from north to south.
76
Okanogan Highlands
The Okanogan Highlands, extending across the northern
section
of
Washington from the Cascades eastvrard into
Idaho, are a westward extension
of the Rocky ltlountains
containing
an old uplifted
erosion surface considerably
dissected by streams and glaciers.
Summit levels are from
4rAgg Eo 5rA00 feet, above which rise peaks to elevations
over 7 r090 feet.
Bedrock is
a combination of
Iavas,
granitic
and metamorphosedmaterials and mineral deposits
are widely distributed.
Five major nort,h-south trenches
traverse
t,he reg ion and conta in
t h e r n aj o r
centers
of
population and most of the important agricultural
production.
Moderate amounts of precipitation
occur at higher
elevations but the valleys receive more modest amounts and
irrigation
is necessary for such intensive agriculture
as
the apple production in the Okanogan Valley.
Coniferous
forests dominate the higher landscapes but give way to a
bunch grass-sage complex on lower southern slopes and in
the lowlands where elevations may be less than I1000 feet.
The winter portion of annual profiles of precipitation
and coef f icienEs of variat,ion is very much l ike t.hose of
stat,ions west of the Cascades
that is the profiles
are
symmetrical about December, the wettest month.
December is
aLso general ly
the least
var iable
month al though this
feature is not as pervasive as in western Washington.
In
factr
dt Chewelah coefficient.s of variation
are nearly
equal in December, January and June.
Also obvious is the
aforenentioned secondary maximumof precipitation
in late
s p r i n g - e a r 1 y s u m m e .r
A t L a u r i e r o n t h e C a n a di a n b o r d e r ,
f or example, the nonths of l'lay and June are nearly as wet
as the wettest winter mont,hs.
The timing of t,his secondary maximum is coincident
p a ci f i c
wi th
movement of
the
anticyclone.
A
rapid
large-scale shift of the general circulation takes place in
most years in early July and the center of the pacific High
shifts
from abour laritude
340 Norrh to approximarely 4go
North (Figure l7).
In Play and June the region escapes
effects
of subsidence and the interior
of Washington and
Oregon is charact,erized by low pressure at the surface and
an upper level
trough which induces a flow of maritime
southwesterly air
from the Pacific
Ocean. The short wet
season of late spring-early summeris the result.
With the
abrupt change in circulation
in JuIy anEicyclonic control
becomes more dominant and precipitation
is reduced.
tow
values of the coefficient
of variation in May and June are
associated with these $/etter months. The amplitude of the
annual profile
of coefficienrs
of variation
is relatively
small, simiLar to those ,for northern Washington stations
west of the cascades.
77
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78
Columbia Basin
South of
the Okanogan Highlands
and east
of
the
Cascades is
an extensive
region,
the
Columbia Basin,
subdivided
by geomorphologists
into
five
areas.
The
Centrat Plains is a low saucer-shaped depression floored by
basaltic lavas and covered by detritus.
A t s o m e w h a th i g h e r
elevations
great,er relief
and with
are the waterville
Plateau in the north, tshe Palouse HilIs to the southeast,
the Yakima Folds to the vrest and the Deschutes-Umatilla
Plateau to the south
south of t.he Columbia River in
north central Oregon. Lower elevations than in surrounding
regions, bedrock formed of basaltic
lavas and low amounts
of annual precipitation
are characteristics
shared by all
of these subregions.
The entire
region is characterized by low precipitation,
less than in the Okanogan Highlands to the north,
but there is considerable variation
in annual amounts and
the pattern of distribution
is relatively complex, affected
by elevation,
exposure and the opposing influences of the
Cascade barr ier
and the Columbia River
gorge "
Lovrest
precipitation
amounts occur where the elevation is 1ow, the
area enclosed and the influence of the Cascade barrier
is
the greatest.
Y a k i m a W S OA P ( e l e v a t i o n = I A 6 4 f e e t ) ,
for
example, has a mean annual precipitation
of 7.gA inches.
Moses Lake 3 E (elevation = L2Ag feet) in the lower portion
of the Central Plains, receives 8.23 inches.
In the yakima
Val1ey and the Central Plains irrigation
is essential for
crop agriculture.
Other parts of the region have sufficient
precipitaLion to support extensive wheat production and livestock
grazing in areas of rougher terrain or less arable soils.
Rosalia, on the eastern edge of the palouse Hi1ls, receives
I8.A2 inches and Walla Walla WSO CI, although at lower
elevation, receives 16.63 inches
being favored by marine
influences
through the Columbia River gorge and perhaps
some orographic
ef f ects of the Blue lvlountains.
On the
Deschutes-Umati]1a Plateau in north central Oregon annual
pr€cipitation
is slighrly
l e s s ( W a s c oa n d H e p p n e r ) .
Annual profiles
of precipitation
and variability
are
similar
to those for stations
of the Okanogan Highlands.
T h e w i n t e r m a x i m u mi s s t i l l
t,he primary one and there is a
strong secondary maximum in lvlay and June.
However, the
profiles
show more complexity, due in part to the presence
of
t,he Columbia River
gorge.
At, Wasco the
secondary
m a x i m u mi s a l m o s t n o n e x i s t e n t , m o r e t y p i c a l o f r e g i o n s w e s t
of the Cascades. At neither Wasco nor Heppner is December
the wettest mont.h. At Heppner , November and Decernber a re
apProximately equal and at Wasco both November and January
receive more precipitation
t h a n D e c e m b e r . A t y a k i m a W S OA p
is
January
decidedly
the
wettest
good
month.
A
79
comparison can be nade with three stations
on roughly the
same
Cascades
latitude
as
west
of
the
Yakima
(Rainier-Ohanapecosh,
Aberdeen).
WSO AP
and
Olympia
December is the $rettest and least variable
month at these
three as opposed to January at Yakima.
S u m m e rp a t t e r n s a r e m o r e c o n s i s t e n t .
July and August
g
e
n
e
r
a
l
l
y
are the driest
t
h
e
most variable
a
n
d
months
of
although at lvtoses Lake 3 E and Rosalia coefficients
in
q
u
i
t
e
variation
high through September. Rainfall
remain
i
n
these months is convective in nature and highly variable
both space and t,ime.
BIue l,lountains
In its broadest sense the term Blue Plountains includes
the hilfy
and mountainous land of northeastern Oregon and
southeastern Washington from the Snake River west almost Eo
The region
Prineville
only 3g miles from the Cascades.
includes a variety
of uplands and intervening valleys with
relief
and elevation increasing toward the central corer the
Wallowa lviountains, which have elevations of Ig tg06 f eet and
the most spectacular alpine scenery in the Pacific Northwest
east of the Cascades.
Increasing elevation results in increased precipitation
in the change from grasses to
which is in turn reflected
shrubs to stands of conifers which cover much of the region.
are Iocated in the protected
Ivlost cl imatolog icat stations
is difficult
to determine annual
and lower valleys and it
precipitation
means for the higher exposed areas but it is
thought Lhat amounts must approach 5g inches.
the form of
in the Blue lvlountains exhibit
Stations
typical of
annual profiles of precipitation
and variability
some
are
there
all
the
eastern
regions.
However,
to the
significant
as compared with stations
differences
north.
s u m m e r 'm a x i m u m i s g e n e r a l l y
The late spring-early
In fact,
throughout rnuch of the region May
more dominant.
is the wettest month of the year rat.her than December or
January.
Of the stations represented in this study this is
true aL Baker KBKR and at Dayville,
but not at Wallowa.
H o w e v e r , t h e s e c o n d a r y m a x i m u ma t W a l l o w a i s n e a r l y e q u a l l n
magnitude to the winter maximum.
July is the driest and most variable month at most Blue
inverse
expected
Flountain
stations.
the
Otherwise,
of
relationship
between monthly means and coefficients
At, Wallqwa March is
variation
is complex and unpredictable.
the
mont,h although
fron
being
the
least
variable
far
than May
wet.test. Winter months are slightly
more variable
continental
and June,
a
suggestion
of
the
increasing
winter
of
inftuence
and asseciat,ed higher
variability
precipitatioR.
YetI at Baker KBKR, while both tlay and June
80
are
dec idedly
lretter
than
any of
the
winter
mont,hs,
coefficients
of variation
in May and June are higher.
The
least variable month at Baker KBKRis February which is the
driest
mont,h between November and June.
At wallowa the
least
variable
month is
March,
followed
closely
by
F e b r u ar y .
precipitation
Certainly
patt,erns in this region over
space and time are difficult
to generalize.
The increased
continental
influence
combines with local
conditions
of
elevation
and
exposure
to
account
for
apparent
inconsistencies
between
monthly
means
and
monthly
coefficients of variation.
High Lava Plains
This region lies between rhe Columbia Basin and the
Brue l.{ountains to
the
north
and the Basin and Range
province
in
the
south
and extends eastward
from the
cascades to the snake River p1ain.
Topographically
it
represents a t,ransition from the Deschutes-umatilla plateau
Eo
the
Basin
and
province
Range
and
exhibits
character istics
of
both.
The region
is
underrain by
horizontal
flows of ancient lavasr largely
uneroded and
covered by younger volcanic materials or stream deposited
alluvium.
rt is one of the driest regions of the pacific
Northvrrest and has a large section of inter ior drainage.
only
in
the
west
does the
Deschutes River
and
its
tributaries
flow entirely through t,he region.
In
the western area the nearly
level
surface
is
covered with recent lava flows and volcanic ash deposits
above which rise numerous cinder conesr volcanic peaks of
moderate height and a number of long low ridges in the
northern
section.
rn the Harney area to the east the
surface
is
even more level
with
plains
broad alluvial
sloping down to the two major 1akes, Harney and tqalheur.
Elevations
in the region range from 3,5a0 feet
in the
Deschutes Va11ey to over 6,AA0 feet in the south.
Annual and seasonal
precipitation
totals
of
are
similar to Ehe central plains of the columbia Basin
Low
varues and only modest changes with el-evation and exposure.
However, there are some interesting
contrasts between the
regions.
rt,,was noted that in the columbia Basin there is
a general increase in annual precipitaEion
from rrrest to
east,
in other
words the
ra inshadowing effect
of
the
cascades is grearest immediatety to the lee.
rn the High
Lava Plains the reverse seems to be the case.
stations
j ust
east
of
the
Cascades (e.g.
Bend, mean annual
precipitation
= 11.94 inches) receive as much or more than
those farther
east (e.g, ltalheur Refuge He, g.29 inches,
8l
and VaIe,
elevation.
9.4L
inctres)
a
factor
not
due to
differences
in
in
are more obvious,
in annual profiles
Similarities
An
particular
the strong secondary maximum in May and June.
maximum is very much
is at Bend where the winter
exception
to the Cascades and the profile
dominant due to proximity
to that of the Cascades and
for the winter season is similar
variable
and least
is the wettest
west,
although
January
McKenzie
the case at
month rather
than
December (as is
and Newport).
Bridge, Corvallis
are
Farther east, dt t'lalheur and VaIe, annual profiles
months
at
Malheur,
wettest
more
irregular.
The three
equal to May and
are essentially
November through January,
month of
v
ariable
t
h
e
l
e
a
s
t
i
s
m
e
a
n
a
m
o
u
n
t
s
.
M
a
y
i
n
June
region
t
h
e
t
h
r
o
u
g
h
o
u
t
m
o
n
t
h
i
s
t
h
e
d
r
i
e
s
t
the year.
July
Of particular
it
and either
or August the most variable'
With the
is ttre month of April.
at these stations
interest
year and
o
f
t
h
e
d
r
i
e
s
t
i
s
t
h
e
m
o
n
t
h
exception of July, April
v
a
r
i
a
t
i
on
in
o
f
c
o
e
f
f
i
c
i
e
n
t
s
extremely
high
exhibits
b
e
c
a
n
I
t
a
n
d
s
p
r
i
n
g
m
o
n
t
h
s
.
vlinter
comparison to other
w
e
t
t
e
r
t
w
o
p
e
r
i
o
d
b
e
t
w
e
e
n
dry
cOnsidered the transitional
periods.
Basin
and Range
south of the High Lava
The Basin and Range region lies
and between the Cascades to the west and the Owyhee
Plains
of a
ttre norttrern portion
It includes
Uplahds to the east.
g
e
o
l
o
gie
p
r
o
v
i
n
c
e
t
o
p
o
g
r
a
p
h
y
,
geomorphic
of similar
targer
t
o
The
M
e
x
i
c
o
.
that extends southward
and climate
structure
r
a
n
g
es
m
o
u
n
t
a
i
n
n
a
r
r
o
w
is a land of long,
Oregon portion
r
e
s
u
l
t
t
h
e
a
r
e
r
a
n
g
e
s
The
whose axes trend north and south.
w
i
t
h
a
r
t
e
r
n
a
t
i
n
g
and are asymmetrical,
of btock
faulting
broad shallow basins.
facing
scarps
steep fault
ranges,
with
The mountain
the
w
h
i
l
e
east or west, are formed of layers of lava
either
a
d
j
o
i
n
i
n
g
debris
washed from the
basins
are covered with
d
r
a
i
n
a
g
e
by interior
slopes.
These basins are charaqterized
large temporary lakes.
Klamath Lake
contain
and frequently
drainage as
is a major exception to the pattern of interior
amount of surface
and more reliabte
receives
a greater
it
is drained by the Klamath
runoff
from the Cascades and it
average
The
into
California.
f Lovling
southward
River
of the basins is above 4'g0g feet and the ranges
elevation
are L,AA6 to 5,ggg feet higher.
growing
season due to hi.gh elevations,
With a short
and few permanently
cold temperatures
and low precipitation
the
supply
water
a reliable
flowing
streams
to
furnish
Natural
limited,
possibilites
agriculture
are
for
erop
82
vegetation
is a grass-desert
shrub cornplex that
the basis for extensive grazing of livestock.
furnishes
The patt,ern of precipitation
distriburion
is quite
similar
to that of the High Lava plains
ro the north,
although
annual
totals
generatty
are
greater.
Precipitation
totals
seem to decline
from srest Lo east
although
the paucity
of
long-term
station
records and
differences
in elevation and exposure make generalizations
difficult.
As noted in t,he annual profiies
the winter
maximum is dominant
more so close to the cascades.
To
t h e e a s t T € . g . a t L a k e v i e w , t h e s e c o n d a r y m a x i m u mi s m o r e
p r o n o u n c e d . T h e m o n t h o f m a x i m u mp r e c i p i t a t i o n
varies from
station to station, but July is uniformly the driest mont,h.
coefficients
of variat,ion in the summermonths of July and
August are extremely high, but through the rest of the year
there
is
a
rather
remarkable
uniformity
of
rnonlhly
coefficients of variation.
83
Figure
18.
and Monthly
of Monthly Mean Precipitation
Annual Profiles
Subset of Network
for 43-Station
of Variation
Coefficients
(Ig4g-Ig7g),
Arranged by Geomorphic S,egion (see Figure 1.6).
84
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FM2S
INTERSTATION CORRELATIONS
Correlation
techniques
have been used frequently
to
the
study
spatial
organization
of
weattrer
and climate
elements.
Successful
analyses of precipitation
data include
(tgOl)
those
by FIiri
who investigated
space correlation
fields
of monthly
and seasonal precipitation
in the AlpsT
.-Brazel
Sharon (tgZg)
in the .Iordan Valley
and
and Ziriax
(tglg)
in central
Arizona.
Correlation
studies by Huff and
Shipp (fg6g)
were made to determine
the optimum spacing of
(L974) was able to
weather stations
in lllinois
and tongley
reveal
dominant
storm tracks
by
on the Canadian Prairies
analyzing
correlation
fields
of
monthly
and
seasonal
precipitation.
pattern
aide in visualizing
As a further
the spatial
of
precipitation
in
the
correlatj-on
Pacific
Northwest
(r)
coefficients
for
were calculate<l
aIl
network stations
using
CorvalIis-State
as the central
station.
University
of Corvallis
The choice
is based on its
location
in the
part
western
of the region,
from which most
the direction
storm systems originate,
and ttre reliability
of its record.
is
arbitrary
However, the choice
and correlation
coefficients
vrere also calculated
with Baker KBKR as the central
station.
maps for
each monttr and the
two
Isocorrelate
(
w
i
t
h
seasons
and for
Corvallis-State
Univ.)
January a3d
July (with Baker) are presented in Figure J.9 page LA3.
of the coefficients
shown here can be
The significance
approximat,ed with
critical
values ^oredicted by statisticaL
theory.
Based on the assumption of a normal distribution
of
the varialrles
involved,
the significance
of r-values
can be
determined
by use of the student's
t-test.
The assumption
distributed
variables
of normally
is very restrictive
and,
as
noted
earlier,
is
seldom
met by monthly
or
summer
precipitation
dab.a series
in
the
Norttrwest.
Pacif ic
However, no normalization
of the data was performed since it
?ras been argued by other
investigators
that
the pattern
of
(McDonald 1957).
isocorrelates
is not significantly
altered
For a sample of 4fr pairs
of observations
an r-value
of
g.3A can be considered
approximately
significant
at. the 95
q.59,
percent
level
of
confidence;
an
r-value
is
of
(Gregory
significant
at the 99 percent
level
of confidence
analysis
f973).
Pyke (fge0) noted that it was
In a similar
safe to assume that
r-values
less than about g.2A are not
significant
greater
whereas r-values
than about ?J.4A are
definitely
significant.
As an aid in seeing patterns
on the
greater
two seasonal maps, areas of r-values
ttran g.6g and
Iess than A.3g are shaded.
f ietds
a.s mapped are
exceedingly
The correlation
complex as expected for the Pacific
Northwest with its great
variety
of
cli.matic
controls.
some obvious
However,
(not
patterns
r-values
are
emerge.
mapped)
Yearly
100
approximately
to
the
equal
seasonal
r-values
are
about
months comprising
the seasons.
wetter
equal
to
months
and
winter
individual
those
generatly
are
than
Winter
season r-values
larger
summer season r-valuesr
drr expected relationship
due to the
more
homogeneous
nature
precipitation.
of
winter
cyclonic
Large-scale
storms in the winter
are more uniform
than
suflrmer
convective
rainfall
by
brought
small
disturbances
in the upper atmosphere.
In both seasons and in all months, there is a general
decay of r-values with increasing distance from the central
station.
Highest
values
are,
of course,
eit Willamette
stations
proximity
Valley
because of their
to Corvallis.
The decay with distance
is more extreme in sufirmer than in
winter.
Ttrere is no single dominant orientation
of an axis
of
maximum correlation.
is
apparent
a
on
One axis
north-south
Iine
from CorvalIis
throughout
the
region.
There is also a zone of very high r-values on the east side
of the Slashington Cascades.
Another axis of high r-values
appears to extend discontinuously
to the northeast
from
Corvallis.
Also,
r-values
in
eastern
and
Washington
northern
Idaho are extremely
high.
for a
This preference
north
to
northeast
orientation
is
a response
to
the
predominant direction
of storm movement ttrrough the Pacific
Northwest.
Sneva and Calvin (1978) found that in eastern
Oregon r-values
between stations
tying
at a bearing
of
about 55 degrees (northeast-southwest)
from each other vrere
at
a maximum.
The most rapid
decay in
r-values
from
Corvallis
is
to the east and southeast
wittr the lowest
values in far eastern Oregon.
(January) show a
Isocorrelates
for Baker in the winter
distinct
axis
of
maximum
correlation
a
on
northeast-southwest
line with a particutarly
rapid decay of
r-values
perpendicular
to
this
1j.ne.
on the
Indeed,
Olympic Peninsula
are the lowest values,
approaching
zero
at some stations.
In summer the pattern
of isocorrelates
with Corvallis
is much the same as in winter,
the most obvious difference
being in the strength
of the correlation
field,
that is,
the magnitude of r-values.
From Corvallis
there exists an
axis
of max j-mum correlation
north
and souttr througtr
the
region.
In all
other directions
is
the decay of r-values
rapid.
In contrast
the extremely
high
correlation
with
stations
in
northeastern
particularly
Washington
is
striking.
Here r-values
exceed A.5O at
some stations,
considerably
higher
than in central
to
Washington closer
Corvallis.
East of the Cascades in Oregon correlation
of
summer rainfall
with
that
at
is
essentially
Corvallis
non-existent.
l0t
study the sunner season
for this
Although by definition
the
September,
five
months from May to
the
of
consists
interesting
and
mask some appreciable
sunrmer r-values
the monthly maps.
as can be seen by studying
differences
high for eastern Oregon
are relatively
For example, r-values
the month of May and ttren decline
and through
in
spring
The Columbia Basin has the lowest
sharply in June and July.
values in June while the Snake River Plain and southeastern
Also, bY July the area of
Oregon are the lowest in July.
in muctt of
r-values
with
is much Iarger
Iow correlation
and most of the BIue
Oregon Iess than 6.IA
southeastern
the most interesting
One of
than 6.2A.
less
Mountains
from
in r-values
however, is the sudden increase
aspects,
the
f
o
r
t
t
r
e
v
a
l
u
e
s
m
o
n
t
h
l
a
t
t
e
r
t
h
e
I
n
t
o
A
u
g
u
s
t
.
July
season.
the winter
for
than
higher
are generally
region
over
9.54.
r-values
Oregon has
eastern
of
aII
Almost
v
a
lues
w
i
t
h
P
l
a
i
n
R
i
v
e
r
t
h
e
i
s
S
n
a
k
e
n
o
t
e
a
b
l
e
Particularly
g
.
6
g
in
t
o
g
.
4
6
t
o
a
,
8
a
g
.
2
a
b
u
t
i
n
c
r
e
a
s
i
n
g
i
n
w
i
n
t
e
r
t
o
of
August.
are
basis
a monthly
on
fields
correlation
These
n
e
q
e
s
s
i
t
a
te
w
i
I
I
i
n
t
e
r
p
r
e
t
a
t
i
o
n
F
u
r
t
h
e
r
complex.
extremely
a
nd
t
t
r
a
n
C
o
r
v
a
l
l
i
s
o
t
h
e
r
s
t
a
t
i
o
n
s
w
i
t
h
mapping Lorrelations
h
o
m
o
g
e
n
e
o
us
i
d
e
n
t
i
f
y
i
n
g
f
o
r
p
o
t
e
n
t
i
a
l
However, the
Baker.
s
t
a
t
i
s
t
i
c
.
t
h
i
s
w
i
t
h
i
n
I
i
e
s
c
e
r
t
a
i
n
l
y
regions
precipitation
102
Figure
Map Series
of
Correlation
19.
Coefficients,
( Dqa-D7e ) :
a) with Corvallis-State
seasonal and monttrly
b)
Note;
wittr
data
r-values
University
data
Baker KBKR - January
-
and July
r
indicate
areas of
Corvallis
Seasonal maps for
greater
than .66 (light
shading) and less than .39
(dark shading).
103
L
o
E
E
3
u,
.ci l
,
I
f,r
i
i
r
,
t
-
O i
l
O ;
Lt)
l
II
.2
i o
l-
o
l
I
o
I
t-
o
.F
.E
\.-
104
l
b
r o
-o
] E
i o
o
z
L
o
-o
o
+
I
o
i >L \
i
r
l
O
J
C
l - l
E
\
,/
l-='
\
E
l
,
o
?
\
t
b
o
-o
E
o
I
o
a
106
is
Lt
, \
i o
=
\r
-__---
\ \
9
L
o
D
L
-o
o
IL
o
=
L
CL
108
->
D
-l
o
-l
C
D
i s
o
.o
E
i o
i { -
o.
o
"0
t,
f
o
f
il0
->
f
l-f
u,
v
dt
\Z
L
o
-Y
o
ccl
-o
b
g
D
c
,-tc t
ill
V.
SECULARCHANGESIN PRECIPITATION
rn this
study a preriminary
examination
has been made
of changes in annual precipit.€iot
throughout
the region.
The period
of record used tor
this
anarysis
is rimited
to
that
for
which
crimatologicar
stations
pacific
in
the
Northwest
have_ been in operation
the instrumental
(or
securar)
period
approximately
the last Loo years.
A
s
an
introduction
to thi;,,set
materi-al
it
is
usefur
to
t
h
e
scene" with an overview of crimatic
history
in the pacific
Northwest over a much longer time scale.
CLIMATIC HISTORY
Paleoclimate
Indicators
The pacific
Northwest
experienced
a great range of
climatic
c o n d j _ t i o n s o v e r t h_eh a st a s € 2 g , A A g y e a r s , v a r i a t i o n s
in climatic
erements consid-e_rabry ff".t",
than in the past
century
and with greater
ef fectJ
o-n the region.
T h e m aj o r
climatic
division
of
the
1ast
2A,AAA years
vras the
termination
of the preistocene
rce Age which ended suddenly
in North American between Lg,A6g .na
L2,AAA years B. p.
(before
present)
a s s h o w n b y n e a r l y - a neav e r y f a s t
responding
indicator
o f c r i m a t e c h a n g e [.e r y s o n
H
a
r
e
r
g
7
4
)
.
Heusser
(1977) '
through
the
stu-ay or
porren
profiles
and peat
stratigraphy,
set
the boundary
between
Iate-gIacial
and
post-glacial
climate at about IA,SgA B. p. in waJnington and
southern British
Columbia.
Although
crimate
associated
with
the
_ the change of
retreat
of
the
cordilleran
ice
sheet
from the northern
section
of the pacif ic Northwest was a crimactic
event i_n
climatic
history,
the most significant
period
for the study
and interpretation
of crimat-ic
tr"rri"i"
the rast
L,aga
years
which
represents
the
rimit
of
accuracy
f
o
r
many
paleoclimatic
indicators
and methods of ,.=".rJh
(Kutzbach
of historical
records.
Three
L have yietded
a wealth
of
r the American West are tree
the
reconstruction
of
past
ke levels
and the evidence of
movements of mountain glaciers.
Many of the studies rerating
to climatic
history
in the
west have been based on dendroclimatic
i".""rtlJJii";".
The
annuar nature of tree rings has been
known for a 10ng time
-for
but the use of tree rings
dating- ana assessing patterns
of temperature
and precipitation
is" a more recent deverop_
menr.
Early
studies
by
(rgrg_rgs6,
Douglas
Lg37),
113
( 1938); Giddings
(tg+g,
Antevs
1953) and Schulman ( 1945,
L947,
L956)
established
the
foundation
for
tree-ring
research
in
North
America.
years
recent
In
computer
applications
and advance statistical
techniques
have been
combined with detailed
physiorogicar
studies
to permit more
detailed
climatic
reconstructions.
(tgtO) gives a detailed
A recent book by fritts
review
of
the
state
of
the
art
in
tree
ring
studies.
Precipitation,
temperature and pressure anomaly patterns
for
the entire
west have been reconstructed
and mapped for much
(fritts
of
the last
millenium
1965, LaMarche and Frj-tts
L97L, Fritts
and Blasing 1973, Blasing L97S).
For the West
as a whole Bradley's
summary of dendroclimatological
studies
should be noted (Bradley 1976c, p. 74)z
is interesting
It
to note that whereas the most
(L94L-I97O)
recent
normal
3o-year
is
indeed
anomalous when compared to records
of the last
L0A-IZA years,
the entire
period
considered
in
this study (approximately
L9SA-L979, may itseLf be
anomalous when viewed
in
context
of
the
last
milleniurn.
If
LaMarche's dendroclimatic
infer(LaMarche I974), then conditions
ences are correct
similar
to
the
most recent
have not
"normal"
prevailed
since
L33g A.
when a
D.
26T-year
spell
"warm-dry"
ended, replaced
by "cool-moist"
condi-tions.
Furthermore,
the
"warm-moist"
conditions
of the period
c. LBTg-I945 may only
have occurred once in the last IIUA years
from
c. IA55 to 1I3g A. D.
Unfortunately
the few tree ring chronologies
developed
in the Pacific
Northwest are in the arid regions of eastern
Oregon and Washington (Stokes,
Drew and Stockton 1973).
No
dendrochronologies
exist
for the humid western areas because
abundant precipitation
would make climatic
interpretatj-ons
difficult..
Keen (f937) studied LZ4g ponderosa pines in 4g
different
localities
in
eastern
and
northeast
oregon
carifornia
and extended a crude index of crimatic
history
back to the year L268 A. D.
He concluded
that
no clear
trends exist
for either
a drier
or wetter crimate over this
period,
that
the years IgAg to 1916 experienced cLose to
normar amounts of precipitation
when compared to the entire
period,
and that
the drought
of
was the most
19I7-1935
severe in the entire
period.
Schulman (tgat)
developed a
chronology of tree-ring
variations
in the Okanogan Valley of
southern
British
corumbia
and north-centrar
washington
for
the period L86g to L94I.
He noted a relatively
r
a
t
e
high
of
growth for the years LgAg to 1B5O; a lower rate
of g,rowth
from I85g to Lggg althougtr l86f was a year of exceptionally
rapid growthi and an increase
from Lgfrg to 1916 followed
by
a severe decll-ne to the lowest levels
in L93B-L93L, followed
by an increase frorn 1931 to 1941 .
114
Lakes in the arid
and semiarid
interior
sections
of
the American west have long
attracted
the attentj_on
of
researchers
concerned with
climatic
ctrange because rake
revels undergo considerabre
and frequent change in response
to
fluctuations
in
temperature
and precipitation.
For
exampre, ancient
and modern revers
in Lake Bonnevirre
of
utah have been studied
extensivery.
studies
Early
by
(tggT) and more recently
Gilbert
by fves (fgag,
IgS4) ana
Antevs (1948, 1955) produced chronorogies
prace the
that
major part of the history
of Lake Bonnevirre
in the tate
Plei-stocene.
studies of rake levers pertaining
to climatic
fructuations in the last two centuries
include that of Hardman and
Venstrom (rgar)
who reconstructed
changes in the rever and
vorumes of Pyramid and winnemuca rakeJ in the Great Basin
from the early nineteenth
century
to Lg$a.
They indicate
that the early decades of the nineteenttr century were quite
dry;
the period
Lg4A to
186A was relatively
dry.
The
decade
of
the
L866s
experienced
greatly
increased
precipitation,
particurarly
the year
Lg67 to rg7l.
The
decade of
the
l88os
was again
quite
dry,
forrowed
by
increased precipitation
through the rgLas and then a steady
decline
to the early r93os.
Lynch (rgag) studied severar
interior
rakes of the west and noted that
they indicate
generarry
heavy precipitation
in the latter
part
of the
nineteenth
century
and
years
early
of
tha
twentieth
century,
amounts not
matched
past
i;
the
4ga years.
Lawrence and Lawrence
( fg6f)
studied
between
2A lakes
central
British
corumbia and northern
california
and were
able
to supplement the findings
of others
high lake
levels in the r87as and rS8os and again in the earry r9a6s,
extreme
dessication
untir
the
middre
and late
r93as,'
forrowed
by a rather
steady
rise
in
the
r94as which
accelerated
in
the
( rgsa) noted rake
r95os.
Fairbanks
rever increases from the tate L93as to almost record revers
by 1958 for severar eastern
oregon rocations
and Friedman
and Redfield
(tgZt)
found a similar
rise
in Soap Lake in
eastern Washington.
High revels
of interior
lakes
in the Arnerican west
have been found to be generalry
coincident
with periods of
advance of mountain graciers
Lawrence (wsa,
i95g ) , the
most dramatic advance in recent centuries
being that of the
rate
seventeenth
and
early
eighteenth
centuries,
the
curmination
of the Little
rce Age.
such ad.vances have been
documented on Mount Hood, Oregon and on other
western
mountains.
studies of more recent gracial
movements have
showed renewed advance since
about
after
rg42
severar
decades of accererated recessi-on.
Dyson (rgag) studied the
shri-nkage of
sperry
and Grinnerl
graciers
in
Gracier
Nationar
Park, Montana and noted a considerable
recession
between r85a and Lgga that become more severe in the early
decades of
the
twentieth
century;
since
1937-193g the
recession
had slowed.
The tendency
for
a readvance was
ll5
Glacier on Mt.
detected by .lohnson (tgS+) on Nisqually
first
(
f
g
S
6
)
a
who noted
b
y
a
n
d
s
u
p
p
o
r
t
e
d
B
e
n
g
s
t
o
n
Rainier
B
a
k
e
r
o
n
M
t
.
a
d
v
a
n
c
e
o
f
C
o
l
e
m
a
n
G
l
a
c
i
e
r
spectacular
(
w
a
s
H
u
b
l
e
y
f
g
S
0
)
t
h
e
m
i
d
d
l
e
i
n
B
y
L
9
5
A
s
beginning
L949.
g
l
a
c
i
e
r
s
i
n
t
h
e
O
l
y
m
p
i
c
s
e
n
l
a
r
g
e
m
e
n
t
s
o
f
able to record
5g
evidence
Corraborating
and Cascades between L947 and f956.
(
1
9
7
f
)
.
the
of
a
s
t
u
d
y
aI
In
et
comes from Franklin
t
h
ey
o
f
M
t
.
R
a
i
n
i
e
r
,
invasion of trees into the tundra zone
w
as
p
e
r
i
o
d
i
n
v
a
s
i
o
n
f
o
r
e
s
t
of
found that the most extensive
p
e
r
i
o
d
t
h
a
t
t
h
e
Nisqually
of time
L928 to 1937, the same
Glacier was receeding rapidly.
Instrumental
Data
northern
the entire
agreement that
There is general
a general warming from about L85g
hemisphere has experienced
in part to
to the L94As (uitchetl
1961, 1963), attributable
in
the
atmosphere
dioxide
carbon
increased
Ievels
of
(willett
Since around
I974).
L95A, Mdtrer 1963, sellers
has been a
ttrere
by the
evidence,
L94A, ds suggested
primarily
at
coolitg,
trend and general
reversal
of this
(Lamb 1966, Budyko 1969, AngeII
middle and high latitudes
episode
and Korshover L977, 1978).
Causes of this cooling
(Wittett
probably are multiple,
including
solar variability
(oliver
activity
L976).
Ig74 and Agee L98g) and volcanic
in the general
documented a broadscale shift
Kalnicky (tgl+)
flow.
However,
to increased meridional
circulation,
a shift
basis
anomalies on a regional
and precipitation
temperature
trend.
Some
hemispheric
reflect
this
do not necessarily
warmed while
have actually
regions of the middle latitudes
trave
and eastern United States,
such as the central
others,
(Wanf and Lawson L97q).
experienced sharp cooling
is the fact that there is
Perhaps of more significance
in
the extreme variations
a growing body of evidence that
to a period of
of recent years is a return
weather patterns
variability.
WahI and Lawson (I979)
climatic
increasing
that the 193g-1969
echoed the concern of many investigators
episode in a thousand
period was the most abnormal climatic
years.
Extreme events of the 1976s such as severe winters
(Oiaz and Quayle
and eastern
in the central
United States
in the West (Shelton
1977, Bates L978,
1978) and drought
this
to refute
done nothing
have certainly
Namias I979)
opinion.
change as determined from instruResearch on climatic
primarily
data.
on temperature
data
has centered
mental
due
strutinized
data have been less frequently
erecipitation
in extrapolating
records,
difficulty
of
to
inhomogeneity
in
variability
point values to a::eal values and the greater
both
space
and
time.
However,
there
have
been
some
in
precipitation
completed
history
of
excellent
studies
West.
parts
the
years
various
of
American
for
recent
precipitation
(WOA )
and
examined
temperature
SeIIers
116
fluctuations
in Arizona and New Mexico since the 1g5os and
discovered
a downward trend
in precipitaLion
since
Lggs,
approximately
one inch per 36 years, due almost entirely
to
a decrease
in winter
precipitation.
Von Eschen (1959)
found a decrease in precipitation
in New Mexico since r9l5
accompanied by rising
temperatures.
severar studies of carifornia
precipitation
have also
pyke (fgOe) noted definite
been completed in recent years.
fluctuations
of precipitation
of rerativery
short duration
(Lg-3A
years),
particularly
in
monthly
rainfall.
In
addition
a sright
downward trend in the annuar totals
of
precipitationr
particurarly
since
apparent
1915, is
at
stations
in
southern
carifornia
and arong the coast
of
central
California.
(].t1
Some very
short
years ) and
seemingry random fructuations
were also noticed
in annual
precipitation
in Catifornia.
Granger (tgll)
also studied
fluctuations
in precipitation
in lowrand
california
and
concluded
that
whire
there
have
been
significant
fluctuations
in precipitation
amounts over the past
rag
years he courd see no regularity
in wet and dry cycles that
would permit predictions
of future precipitation.
and temperature
fructuations
arong the
- Precipitation
British
corumbia coast were examined by crowe (rgog)
who
noted a rising
trend in mean annuar temperature
from rgaa
to L95a but no significant
increase or decrease in mean
annual precipitation.
some of
these
regional
studies
precipitation
of
fructuations
have incruded data from oregon and washington
stations.
The
most
usefur
work
for
students
of
precipitation
in the pacific
Northwest is that of Bradrey
(tgZ6a,
L976b, I976c) who reconstructed
the precipitation
history
of
the
Rocky Mountain
states
from instiumenLal
data, i.e.
since about Las6.
using earry records from alr
the western states
he was able to document variations
in
precipitation
for
the
latter
harf
of
the
nineteenth
century,
comparing precipitation
totars
to the decade of
the r95as average over much of the western united
states
from at least
1865 to Lg9g.
summers LgTg-Lggg were drier
than the 195Os.
Faf Ls \^'ere very dry at times over 1arge
areas in the latter
parL of the nineteenth
century.
For
the entire
instrumentar
period his anarysis
is reslri-cted
to the states of rdaho, Montana, wyoming, utah and cororado
and ttre data are compared with the Lg4r-Lg7g normal.
His
findings
513):
are
summarized
as
follows:
(Bradley
L976a,
Generallyr
was high
in the
lg90s,
.precipitati-on
IgIOs
and/or
L92As,
L94As
and
L96Us.
Other
decades
were
relatively
particularly
dry,
the
I930s.
Springs
L94L-L97A were wetter
than
ttre
previous
3g years,
but
the period
was
IBgl-191O
wetter
than the I94L-L979
averages.
Considering
117
p.
the
was probably
tg+t-I979
summer preciPitat.ion,
most anomalously wet period for at least 110 years
Over much of the Rockies
and perhaps much longer.
FalI
wet.
extraordinarily
were
the
I966s
low in the L95As,
precipitation
was exceptionally
relatively
average was still
but - ttre I94I-L969
than the l890s, 1910s
drier
high, though generally
in recent decades
and l92as.
winter precipitation
less tl.an was characteristic
has been considerably
except
of the late tgth and early 2AEh centuries,
centered
anomaly Patterns,
in
Recurrent
Idaho.
the
of
are characteristic
southern
Idaho,
over
winter record.
the
is considered
secular period
When the entire
p
a
r
t
i
c
u
l
a
r
,
i
n
a
n
o
m
a
l
o
u
s
;
i
s
recent
"normal"
high and
has been unusually
sunrmer precipitation
low.
One hundred
precipitation
relatively
winter
l^tas
the
Rockies
of
years
climate
ago
the
but
and springs
winters
by wetter
characterized
falls
summers (and in some areas) drier
much drier
of the region.
climate
compared to the post-Lg4l
ANALYSIS
Precipitation
Data Series
precipitation
concerned with
of studies
The majority
analyses
d
e
t
a
i
l
ed
p
e
r
i
o
d
i
n
v
o
l
v
e
d
h
a
v
e
data for the secular
a number
c
o
m
b
i
n
e
d
h
a
v
e
o
r
stations
of a few widely scattered
degree
h
i
g
h
t
h
e
average.
Given
into a regional
of stations
it
p
r
e
c
i
p
i
t
a
t
i
o
n
in Pacific
Norttrwest
variability
of spatial
f
o
r
t
h
e
s
e
r
i
e
s
r
e
t
i
a
b
l
e
g
e
n
e
r
a
t
e
a
to
would be impossible
o
f
n
e
t
w
o
r
k
a
d
e
n
s
e
s
t
u
d
y
in this
region.
Instead,
entire
has been analyzed.
stations
individual
data
precipitation
long-term
of
The reconstruction
task
l
a
b
o
r
i
o
u
s
m
o
r
e
a
Northwest htas
in the Pacific
series
h
i
s
t
o
ry
b
a
s
e
.
T
h
e
d
a
t
a
than was ttre assembling of a A[-year
w
elI
i
s
r
e
g
i
o
n
t
h
e
i
n
observations
climatologicalof
(
f
g
Z
6
a
,
T
h
ey
(
f
g
O
O
)
L
9
7
6
c
l
.
and Bradley
described by Roden
b
e
i
n
g
o
b
s
e
r
v
a
t
i
o
n
s
p
r
e
c
i
p
i
t
a
t
i
o
n
of
have found no indication
p
r
i
o
r
t
o
1
8
4
9
W
a
s
t
r
i
n
g
t
o
n
in Oregon or
recorded
officially
d
a
y
p
r
e
s
e
n
t
n
e
a
r
a
t
Fort Steilacoom
when records were kept
Washington.
PuyalIup,
on a
sites
In the 1850s data were recorded at several
Fort
F
o
r
t
Da}Ies,
for example at Astoria,
continuous basis;
at
Fort
in Oregon and
Vancouver and
Haskins and Fort YamhiII
o
b
s
e
r
v
e
r
s
Were either
Early
Fort WalIa Walla in Washington.
to the
r
e
p
o
r
t
i
n
g
p
o
s
t
s
v
o
l
u
n
t
e
e
r
s
o
r
surgeons at military
of
c
o
o
r
d
i
n
a
t
i
o
n
t
h
e
L87g
In
Institution.
Smilhsonian
t
h
e
C
h
i
e
f
t
o
and record keeping was transferred
observations
S
e
r
v
i
c
e
The Signal
in the Department of War.
Signal Officer
118
maintained
the network untir
Weather Bureau was established.
I
ilury
lggl
when the
u.
s.
until
the earry
r89os the observing
network was thus
sparse and the majority
of stations
estabrished
remained j-n
operation
for only a few years.
For the entire
nineteenttr
century records of more ttran Lg years duration
anywhere in
the western united
are rare and the .vast majority
states
were kept
for
less
than five
years.
However, as noted
earlier,
(fgZOa,
Bradley
I976c)
was able
to
use the
avairable
data to present a reasonabry detailed
picture
of
precipitation
fructuations
over the nocky tuountain states
and the Pacific
Northwest
for the years lg5l-rg9o.
This
excerrent
study shourd be consurted by anyone interested
in
nineteenth
century precj-pitation
in the American vrest.
The approach
in this
study was to work excrusively
.
with continuous
precipitation
data series,
where possible
those extending
from some time in the nineteenth
century up
to the present.
After
the establishment
of the weather
Bureau in 1891 ttre observing
network became much more dense
and by Lgag there were approximately
163 reporting
stations
in oregon and washington,
many oi which have continued
uninterrupted
to the present day..
A network of 7a long-term
stations
was serected
for
analysis,
33 in Washington and 37 in Oregon.
For most of
the statj-ons,
data for the entj-re period were obtained from
crimatologicar
Data - Annual summaries
and
from
the
N.O
essary data for
the
early part of the record were taken from guttetin
w of the
u.
s.
weather
Bureau
which
includes
data
from
the
establishment
of
stations
until
L93g, and from Greeley
(f8eg) and Greeley and Gtassford
(t8gg).
The distribution
of these stations
reflects
the settrement
pattern
of the
region
and is weighte,il toward the more popurated
areas.
Therefore,
it
was necessary to incrude
severar stations
with
shorter
histories
in order
to filt
out the network
geographicalry
(tr'igure 2a).
This
network is
listed
in
Tabre 5 with
the period
of continuous
record
for
annuar
(water year) precipitation,
the mean and standard deviation
for ttre period of record and annual totars
for the extreme
years -- the two wettest
and the two driest.
Each of these precipitation
data series
represerits
a
time
series
a sequence of
observations
afranged
in
temporar order.
The study of changes and fructuatiorrs
in
climatic
elements is essentialry
a problem in time series
anarysis
and the amount of information
in a series depends
directly
on its length.
lt9
WGdon
O
--Hermislon
a
Mcr\4imvillo ErrocodoO2SE
Dufur
Condon
Pendle*onWSO AP
a
Hcppn*
a
loGrondq
Wollswo
a
a
a
Solqm WSO AP
Dchoil
a
t
N.?-a
Eolgr XBKR
a
a
Coruolli: - Sr. Uniy
o o albon,
Evgcnc wso
o
Ap
Doyvilla
o
co:codio
Princvillc
Send
o
a
Burns WSO Cl
O
RoscburcKQEN
Gronls Pots
I
Ashrond
Rivmidc
Fremont
o
Klonolh Fqlls 2 ssw
lqkeviry 2 NNW
Figure
Network of Long-Term
Stations
29.
are in Table
Descriptive
Statistics
Study.
120
Used
5.
in
this
Table 5
Long-Term
Stations
(all
data in inches)
(OREGON)
Years
Max ( year )
Mean
Min ( year )
Station
E-ooB llbany*
tge-es-rgte
ffir
0304 Ashlantl
L88g-t979
L9.62
4.54
75.89
13.45
L L 2 . e 2 ( 1 9 7 6)
L s g . 2 2 ( 1 9 5 5)
4 3 . 3 s ( 1 e 2 8)
4 5 . s r ( 1 9 7 7)
L89g-L979
11.32
2.As
2 L . 3 2 ( 1 8 9 4)
1 9 . 2 5 ( 1 9 5 6)
s . 8 9( r 9 r 9 )
6 . s 5 ( r e 3 7)
1979-1979
57.5S
13.86
L56.73 ( 1894)
L56.54(r89s )
27 .s7 (L924)
3 S. 8 5 ( 1 9 3 4)
L9g3-L979
L2.23
3.73
22.7s(L957)
2 s . 8 7 ( 1 9 4 8)
4 . 3 s ( 1 9 s s)
6 . S e ( L 9 7 7)
1893-1979
rO.89
3.17
t9 .98(L906)
L7.25(L922)
5.24(1924)
5 . 3 8 ( 1 9 2 9)
1433 Cascadia
L9g9-L979
62.L2
8.83
s r . 7 9( r e 1 6)
g 1 . 9 8 ( r 9 4 3)
43.73(L9771
44.55(r973)
I755
L9ga-L979
L2.74
3.96
2 1 . 3 6 ( r 9 4 8)
2 g , 9 2 ( 1 9 6 5)
6 . 6 3( r 9 3 9)
7.es(L9491
1852 Corvallis
State Univ.
L89g-L979
4q.46
7.79
57.7s(L974)
5 8 . 8 2 (r 9 7 1 )
2 4 . 6 6 ( r 9 7 ?)
2 4 . 9 7 ( 1 9 4 4)
2168 Dayville
1895-1979
Lt.7g
2.8s
2 s . r 3 ( 1 9 s 8)
18.87(1e48)
6 . e 7 ( 1 9 4 9)
7 . 4 7( t 9 r 6 )
2277 DetroLt
L9ro-L979
74.95
r3.95
244O Dafur
r9rs-1979
L2.24
3.45
2 L . 4 3 ( 1 9 1 6)
19.95(L9271
2 SE 1 9 1 0 - 1 9 7 9
57.27
9.33
76.98( re56)
76.77(1974)
4 g . r g ( L 9 7 7\
40.LA(L924)
27O9 Eugene
WSO AP
1891-1979
49,58
9.L2
74.r8(1974)
6 3 . 9 7( L 9 7 2 )
23.68(Le24)
2 3 . 7 4 ( L 9 7 7)
3995 Fremont
19rS-1979
L9.50
3.46
2 t . 9 4 ( r . 9 s 6)
19.9s(r965)
3.53(19ss)
4 . 5 2 ( r 9 2 9)
Lg9g-L979
39.34
8.gl
s L . 2 5 ( 1 9 5 6)
4 9 . 9 s ( 1 8 9 6)
r3.s6( L924\
L 5 . s s ( L 9 7 7)
r899-1979
as.5a
13.87
1 3 1. r S ( r 9 3 3 )
r z s . g 2 ( 1 9 4 3)
s 3 . 3 2 ( 1 9 2 e)
5 7. L 2 (r 9 3 S )
0328 Astoria
l8s4-1979
WSO AP
( F t . s t e v e n s 1 8 7 7 - 1 8 8 3)
O417 Baker
O471
KBKR
Bandon
2 f,lIE
6694 Bend
1176 Burns
WSO CI
Condon
2693 Estacada
3445 Grants
Pass
3770 Headworks,
Portland
Vt. B .
6 1 . 2 5( r e 7 4)
s 9 .s s( r 8 e 4)
2 8 . r 8 ( 1 9 4 4)
2S.99(L9271
2 7. e 3( 1 9 5 6 )
8 . 3 6( r 9 s s)
1 r . 2 6 ( 1 8 8 3)
LLg.49(L972)
L S 2. 6 5 ( r 9 7 r )
2rI;@1l
4e.7s(t926)
53.48(L977)
s.53(L9771
7.2L(r939)
3827 Heppner
L89S-L979
r 3. 4 3
2.63
2 s . 6 3 ( 1 9 4 8)
r 8 . 5 5 ( r 9 1 2)
8 . 2 4 ( r 9 3 e)
9 . s 2 ( r 9 2 9)
3847 Hermiston
L 9 g 7- r 9 7 9
8.55
2.14
r3.89(1958)
13.73(1974)
4 . 4 3 ( 1 9 S 8)
s.48(re35)
12'.1
(OREGON)
Station
-4gas
Hooa River
Exp. Sta.
Years
remzg
llean
5Tl6s
StDev
@
Max( year )
Min ( year )
L3=.Z,ri57.7)
6F'6T1694)
5 0. 5 5 (t s e e)
L 4 . 74 ( L 9 2 4 )
5.6r ( L926)
7 . 2 L 1l e 2 4 )
4505 Klamath Falls
2 SSW
1898-1979
13.35
3.8r
23.r8(L927l22.79( r9s5 )
4622 Lacrande
1899-1979
19.43
3.52
29.s4(L9L2)
2 6 . A s( 1 e r 3 )
L O . 4 s ( 1 9 7 3)
1 1 . 9 3 ( L 9 7 7)
4676 Lakeview
2 NNVE
1885-1979
14.58
4.52
2 6 . L 5 ( L 9 s 7)
2 s . 2 4 ( 1 8 9 4)
5 . 6 9 ( 1 9 2 4)
6 . 9 e ( L 9 7 7)
5384 l,lcMinnville
1888-r979
42.90
e.9s
6 5 . 7 5 ( 1 8 9 7)
6s.23(L9?A',l,
2 3 . 3 8 ( 1 e 7 9)
2 3 . 5 5 ( L 9 7 7)
6O32 Newport
L892-L979
68.11
L2.93
99.14(t974)
4 2 . ? 6 ( 1 9 7 7)
4 3 . s 5 ( 1 9 2 4)
9s.s4(re69)
6546 Pendleton
Lggg-L979
l3 .13
2,99
2 s . 2 s (r 8 9 4)
1 8 . 6 6( 1 9 r 2)
7.23(Le73)
7 .67( re6s )
6749 Portland
KGW.rv
r872-L979
42.43
I .88
7 L . 8 2( 1 8 8 3)
6 9 . 5 1( 1 8 7 5)
27.L8(r924)
2 7 . 6 L ( 1 9 7 7)
6883 Prineville
1897-L979
9.47
2,42
16.28(1958)
L 5. 4 9( r e 7 8)
4 . 9 8 ( 1 9 3 9)
7268 Riverside
1898-1979
9.Iq
2.66
r6.24(19r7)
15,99(r913)
4 . s L ( 1 e 3 e)
4.23(L977|
7331 Roseburg
KQEN
r878-1979
32.59
7.92
4 9 . 8 6 ( 1 9 5 6)
47.64(1974)
r5.34(19771
r8.s2(1924)
7500 Salem
VJSOAP
r893-1979
39.53
7.7L
58.48( L974)
s 8 . 4 2 ( 1 8 e 4)
29.37(r977)
24.48(L924)
84O7 The Dalles
1875-1979
L3.42
4.gS
2 4 . 3 9 ( 1 8 8 1)
2 4 . 3 L ( I 8 B / t)
4 .43 ( t977 |
5 . 3 8 ( 1 e 6 8)
8797 Vale
L892-L979
9.97
2.35
r5.48 (L954)
L 4 . s 9 ( r 9 7 S)
3 .6r ( r94e )
4.73(r939)
8997 Wallowa
r9s4-L979
1 7. 5 2
3.55
2 3 . 7 L( 1 9 s 6)
23.69(l9se)
7.76(L929)
e.47(Le24)
9668 Wasco
r9s8-1979
ll .65
2.69
1 7 . s 9 ( 1 9 5 1)
r7.35(1916)
6 .52(L977 )
6 . 6 s ( r 9 2 9)
9213 westonr
Lggg-L977
22.54
5.29
3 5 . 9 9 ( 1 9 7 4)
32.74(L9A4',l,
L 2 , 2 3( 1 9 2 9)
1 3 . 0 3( r e 4 4 )
r{so AP
122
s.s8(rgss)
(WASHTNGTON)
Station
Yeara
llean
StDev
L2.56
Mar ( year )
uin ( year )
OO68 Aberdeen
189r-1979
82.59
6176 Anacortes
I893-r979
26.L6
4.73
3 e. 4 4 ( r 8 e 4)
34.94(r918)
L 7 . 5 7 ( 1 e s 8)
L7.L4(L944)
6?29 Blaine
1894-I979
45.79
7 .93
5 e . 4 4( 1 9 3 4)
s s . 4 8 (r 8 e 4 )
2 5 . A 4( 1 9 7 9)
2 5 . 3 1( 1 9 2 9)
9872 Bremerton
1898-r979
41.15
9.49
7 L . L 2 (1 9 7 4 )
6 6 . 9 9( r e 5 6)
2 2 . 6 s( 1 9 3 e)
23.3A(L944)
1233 Cedar
1899-1979
LO4.L9
]276 Centralia
189r-1979
45.49
7.8r
6 6 . 8 3( r 9 r 5 )
60.691r9s6)
2 8 . 8 8 ( 1 9 4 4)
2 9 . 7 7( r E e r )
1484 Clearbrook
L9S3-L979
47.25
7.67
67.s5(re72)
6 3 . 6 2( r 9 6 4)
3L.04(re29)
3 r . 5 4 ( r 9 7 9)
1564 CIe Elun
I899-r979
22.95
5.62
3 9. 5 7( 1 9 s 9)
38.ss(te72)
1 2 . 7 A ( 1 9 7 7)
L3.69(l-944)
1893-1979
29.L4
4.27
3 L. 9 6( 1 8 9 4)
3 r . 0 6 (1 e 4 8)
L s . 2 8 ( 1 9 7 7)
1 1 . 9 8 ( 1 9 6 6)
1550 Colville
I898-1979
16.43
3.42
2 5 . 3 9( 1 9 6 9)
24.Lr(L974)
Ls.q6(1929)
LO.24{L924)
1665 Conconully
196A-I979
L4.gs
4. r3
2 7. r r ( r 9 4 r )
2 6 . 7 6( 1 9 3 7)
7 .22(L93r',)
7.79(re7e)
2565 Ellensburg
1893-r979
8.97
2.42
1 4 . 7 3( 1 9 1 6 )
L4.L7(L9s7)
4 . 2 s ( L 9 73 )
4.25(L9791
4154 Kennewick
1895-1979
7.35
2.L3
r5.s6(1948)
L 2 . 4 7( 1 9 1 6)
3.76(19A8)
3.85(r909)
4486 Landsburg
L9S3-L979
55.21
8.49
7 4 . L 6 ( 1 9 4 8 ) 3 9 . s 3 ( 1 9 7 7)
7 3 .25(L972',t 4 s . 4 9 ( L 9 3 0 )
1 8 8 4 -r 9 7 9
92.24
2r.32
6639 Odessa
19g4-L979
9.92
2.54
t 9 . 2 9( 1 9 4 8 )
r6.4s(re4r)
5096 Otga 2 SE
L890-L979
29.L3
4.92
4 0 . s 2 ( 1 8 9 4)
3 8 . 7 6( 1 9 6 4 )
6114 Olympia
WSO AP
1878-t979
5L.20
79.32
79.sr(]878) 27.sr(1944)
7 s . 5 6 ( 1 9 1 6 ) 3 r . 5 8 (r 9 2 e )
6624
I879-r979
25.54
5.s3
3 6. 7 1( r 9 1 6)
1 4 . 9 9( L 9 4 4 )
3s.89(18e4) l5.sl(r926)
1586 Co]fax
589I
Lake
I
NW
Neah Bay I
Port
Angeles
E
123
t5.9I
L s s. e 7( r e 3 3)
l o s . 8 1( r e 5 6)
5 5 . 7 7 ( L 9 7 ?)
5 6 . 2 8( 1 9 7 9)
r 3 4 .s s( r e r 6 )
7 6 . 9 2( 1 9 3 0 )
r 3 3 . 3 3 ( 1 9 1 8 ) 76.2s(r9r5)
r+s.04(1e75) 57.7L(197e)
r 4 s . 6 5 ( r 9 7 4 ) 6 5 . e 9( 1 9 3 7)
4.67(L92e)
s.13(1e49)
r3.9s (L929)
L9.s9( 1e7e)
(WASHINGTON)
StDev
Mean
Years
station
Max ( year )
tlin (vear )
L874-r979
L9.24
3-Ag
3 s . 3 6 ( r S 7 5)
2 9 . 3 s ( 1 8 7 5)
L O . 2 7( 1 9 3 S)
r 2 . 5 5( L 9 2 4 )
1894-r979
29.63
4.24
3r.s5(r9s9)
29.68(t927,
r 3 . 1 9( r 9 ? 7)
r3.53 (L9241
r892-L979
17.98
3.84
3 L . 7 2 ( 1 9 4 8)
2 7 . 2 3 ( 1 8 e 7)
9.sr( Lez2)
r979-r979
34.L4
6.39
5 7 . 3 7( 1 8 7 9 )
4 6 . 6 2 ( 1 9 4 8)
2L.2s(r944)
2 2 . 5 8 - 1 9 2 9)
7567 Sedro WooleY
I897-1979
46.93
7 .7?
6 e . s s (1 9 s 9)
6 3. 5 7( r e 3 3)
3r.18(1979)
3r.34( L9291
7773 Snoqualmie
FaI Is
1899-1979
58.31
LA.L9
8 2 . 3 6 ( 1 9 4 8)
89.2L(L9721
3e.56(1977)
4 l . 9 1( r 9 3 S )
7938 SPokane
tfso AP
rs82-1979
16.s8
3.75
2e.78( r948 )
2 3 . 8 9 ( 1 8 e 7)
8 . ? 9 ( 1 9 2 9)
9.83 ( L924)
8286 Tacoma
CitY HalI
r884-1979
38.19
7.L5
5 3 . 6 0 (1 8 9 4 )
5 2 . s 4 ( r 9 S 3)
2 L . 6 6 ( 1 9 5 2)
2 3 . 9 2 ( 1 9 3 S)
8332 Tatoosh
Island
1879-1956
aQ.47
13.71
1r6.Ss(r879)
Lr2.S2(L905)
54.33(t929)
6 s . 9 9 ( 1 9 3 7)
1899-r979
38.65
6.64
5 5 . 4 4 ( L 9 74 l
5 3 . 2 s ( 1 9 5 5)
2 5 . 7 2 ( 1 9 7 7)
26.se ( 1924)
1873-1979
16.13
3.r8
2 5 . 4 6( r 8 7 7 )
2 4 . 5 5 ( 1 8 9 4)
9 . 8 7 ( 1 9 2 9)
r a . s s ( 1 8 7 4)
9gL2 WaLeYville
r89r-1979
LL.O7
3.O2
2 3 . 8 4 (1 9 4 8 )
L 7 . 4 9 ( 1 8 9 7)
5 . 2 7( L 9 7 7 ,
5 .73( L979)
9238 Wilbur
Lggg-1979
L2.3s
3.SA
25.26(re48)
L B . s 7( r 9 g r )
6 .48 ( L929)
6.s1(re30)
9465 Yakina
WSO AP
t9tg-1979
7.36
2.L2
L 4 . 2 5 ( 1 9 5 6)
r2.s8(Le74l
3.921L979)
4 . 1 9 ( 1 9 3 0)
6678 Port
Townaend
2 Mil
6789 PuIIman
7189 Rosalia
tfso*
7488 Seattle
WBr
8773 Vancouver
4 NNE
893I
WaIIa Walla
wso cr
* Stations
not on 46--Year network
44 39N L23 g6w
6008 AlbanY
(atiany No. 2 since f963)
EIev.
= 226 feet
26w
Elev.
= Lggg feet
9213 Weston
45 5ON Il8
7488 Seattle WSo 47 36N L22 2gu EIev.
(Seattle ElilSUl{SO since 1972)
48 23N
8332 Tatooeh
Island lf. B.
L24 44w
EIev.
124
= 14 feet
= lg1
feet
9.96(r973)
Three components are generally
recognized
in any time
series:
a.
the over-all
or long-term
trend
in t h i s c a s e ,
the secular trend;
b.
fluctuations
about
the
trend
of
a periodic
(cyclical)
or aperiodic
nature;
c.
irregular
or random variations.
A great
variety
tests
of statistical
to detect
and
define these components has been developed and utilized
by
numerous investigators
in the field
of climatic
ctrange.
There is no question that research findings
often vary with
the form of analysis
ttrat is applied to the data.
For this
reason ttrree different
approaches have been taken in this
study:
one to detect
trend
secular
in the annual
and
precipitation
seasonal
seriesi
a
second
to
detect
short-term
trends
and fluctuations
in the series
with
a
filtering
technique;
to compare annual means
and a third
and variability
for each decade with those for the entire
period
r
e
c
o
r
d
of
at each station.
Methods used here are
fairly
routine
and generally
accepted as being appropriate
for the analysis of climatic
change (t*litchetl et aI 1966).
Trend
The most tikety
alternative
to a totally
random data
series
is
usually
some form of trend.
least
A linear
squares regression
is often
applied
to define
a trend.
However, if a non-linear
trend exists
this
tectrnique will
not detect
it.
study the presence or absence of
In this
trend was thus tested
for in two ways.
One is the use of
(Kendall
the KendaII rank statistic
L97g) which has the
po\iter of detecting
a non-linear
as weII as linear
trend.
Additiona1ly,
the test is robust -- meaning that departures
from a normal distribution
do not matter.
The Kendall rank
(") is def ined as follows:
statistic
r=
-t
(7)
To determine
P,
xt,
is compared
the value of the first
term
with
aII
later
terms in the
aII
subsequent
series.
values
of the
series
series,
and the
l;:""":":I" "* :; =";.?i""u
T3,;1,":;, "??l'.?x;
;i? ":::"?rifi
and
so
on-
for
The rank
statistic
approximates
for
n greater
than
used
LA and is
ficance
of a trend
by comparison
with
every
term
of
the
a normal
distrj-bution
to
assess
the
signithe value:
(8)
(T)r=olb
125
of the normal
level
probability
the desired
is
where t^
The value .of t is
t-test.
for
a two-tailed
aistribrft.ion
a downward
for
and negative
an upward trend
positive
for
data
for the annual precipitation
lrend.
The rank statistic
Significance
is noted in Tab1e 6.
for each station
series
and the more
the
both
9g percent
at
the
statistic
of
The
restrictive
95 percent levels of confidence are noted.
2I).
are also mapped (figure
results
are
not
only
that
immediately
be
seen
can
It
Northwest
the
Pacific
around
precipitation
amounts
of change
but so too is the direction
Lremendously variable
data
the station
hatf
over time.
In Oregon approximately
(2Ll
a
and half
(16)
yield
a positive
lt-vaIue
series
are
positive
values
the
of
Five
negative
value.
level
percent
the
at
9g
significant
statistically
(Headworks, betroit,
Eugene, Condon and Weston) and five of
(Roseburg,
DaIIes,
The
Fremont,
negative
values
the
for
p
r
e
f
e
r
e
n
c
e
g
e
o
g
r
a
p
h
i
c
n
o
i
s
T
h
e
r
e
Pendleton and Baker).
a
n
d
no
s
t
a
t
e
t
h
e
i
n
a
n
y
w
h
e
r
e
t
r
e
n
d
s
positive
or negative
a
i
s
t
h
e
r
e
a
l
t
h
o
u
g
h
l
e
n
g
t
h
,
r
e
c
o
r
d
with
firm relationship
t
h
e
w
i
t
h
s
t
a
t
i
o
n
s
t
h
e
a
t
v
a
l
u
e
s
negative
for
tendency
Astoria WSOAP, with the longest
Iongest periods of record.
not
is
it
but
value
negative
a
has
data
series,
l
e
a
s
t
LAg
a
t
w
i
t
h
s
t
a
t
i
o
n
s
AII
significant.
statistically
a
t
R
o
s
e
b
urg
s
i
g
n
i
f
i
c
a
n
t
trends,
years of data show negative
t
he
p
a
r
t
t
o
i
n
d
u
e
This is certainly
and at The Dalles.
inclusion
of the wet decade of the t880s.
pattern
emerges
a clearer
of washington
In the state
tested
s
e
r
i
e
s
t
h
e
33
Of
with regard to changes over time.
A
v
a
l
u
e
.
n
e
g
a
t
i
v
e
y
i
e
l
d
e
d
a
24
for
the rank statistic
century
last
the
precipitation
for
downward trend in annual
However, only six
the state.
throughout
appears to prevail
and there are
s
i
g
n
i
f
i
c
a
n
t
of these series are statistically
At
trend.
p
o
s
i
t
i
v
e
a
exhibit
which
stations
several
is
t
r
e
n
d
t
h
e
of
Wastrington
and Seattle-Univ.
Bremerton
y
e
t
t
h
e
y
(
a
t
B
r
e
m
e
r
t
o
n
)
significant
,
positive
statistically
s
i
g
n
i
f
i
c
a
n
t
s
t
a
t
i
s
t
i
c
a
l
l
y
wittr
lre
surrouncled. by stations
or state
any regional
that
is clear
downward trends.
It
g
roup
of
t
h
e
b
y
be influenced
certainly
average
would
T
he
c
o
n
s
i
d
e
r
e
d
.
r
e
c
o
r
d
and the period of
selected
stations
i
s
E
B
a
y
I
WB and Neah
Island
of
Tatoosh
comparison
t
o
p
r
o
x
i
m
i
t
y
c
l
o
s
e
ifi
These two stations,
illustrative.
(
9
5
r
a
n
k
p
e
r
c
e
n
t
)
yierd
a significant
both
each other,
a
t
T
a
t
o
o
s
h
n
e
g
a
t
i
v
e
positive
at Neah Bay I E,
statistic
is only
Island WB. The period of record at Tatoosh Island
y
e
a
r
s
a
f
t
e
r
1966
\rtet
A number of unusually
through f 966.
p
o
s
i
t
i
ve
a
to
trend
to change the overall
are sufficient
period
to
1979 is
value
at Neah Bay 1 E when the entire
considered.
( for
stations
for all
Linear trend was also calculated
method
by the standard
both annual and seasonal data series)
the
of
The significance
regression.
squares
of
least
1?6
Table 6
Trend Statistics
in Inches per Year
Values
Level of Significance
rr95t
t9gl
Station
(period
of
record)
Rank Statistic
(t)
Regression
Coefficient
Winter
Annual
Suffiler
(oREGON)
gggB
9304
9328
9417
O47l
O694
1176
1433
t?55
1862
2I68
2277
2446
2693
2769
3095
3445
3779
3827
3847
4A63
4566
4622
467O
5384
6932
6546
6749
6883
7208
733I
7590
84O1
8797
8997
9968
9213
-.582
Albany (1884-1974)
-.966
Ashland (l88g-r979)
-.111
Astoria
t{SO AP (1854-1979)
-.148r*
Baker KBKR (LA96-L9?9)
-.SSA
Bandon 2NNE (f879-I9791
-.tgl
Bend (L993-L9791
+.56L
Burns l{SO CI (1893-1979)
-.9L6
(1999-1979)
Cascadia
+.153*
Condon (1908-1979)
CorvaIIiB-State
-.934
( I89O-1979)
University
-.s24
(1895-r979)
DayviIle
(r91g-r979)
+.238**
DeLroit
(L9L6-L979)
+.L39
Dufur
-.115
Estacada 2 SE (19fO-1979)
+.235**
Eugene wSO AP (189I-1979)
-.294**
Frernont (191S-I979)
+.9L3
Grants Pass (f890-1979)
Headworks, Portland
+.13I*
Water Bureau (1899-f979)
-.o57
Heppner (1896-1979)
(L9O7-L979)
+.988
Hermiston
Hood River Exp.
-.o94
Sta. (1885-r979)
Klamath FaIls
+.99I
2 SSw (1898-1979)
-.Agt
LaGrande (1899-1979)
+.9L6
Lakeview 2 SSw (1885-1979)
( 1S88-1979 )
+.57A
McMinnville
+.969
Newport (1892-1979)
Pendleton WSOAP (1899-I979)-.2L9**
Portland
KGw-Tv (LA72-L979) -.533
prinevirle
(1897-1979)
+.L27*
-.gdl
(1898-19791
Riverside
-.134*r
Roseburg KOEN (1878-1979)
+.965
Salem wso AP (1893-1979)
-.258**
(1875-1979)
The Dalles
-.gtt
Vale (L892-L979)
(L9O4-L979)
+.979
l{allova
-.585
Wasco (L998-I979)
+.1I8*
weston (f899-1979)
127
-.943
-.933t
+.glt
-.996
+.035**
-.91r
-.9r3
-.a44
-.9L9**
-.925
-.s23
+.0I1
+.o29
+.955
-.sII
-.ogr
-.018r*
+.69r
-.9L9*
-.gLg
+.O92
-.929
+.9L9
+.oLg
.ggo
+.249**
-.936*
+.086
+. l2gr*
+.947r*
+.ggg
.sog
-.ss6
+.2L9**
-.o22
+.974
+.143**
+.649**
+.oLz
+.o99
+.965
+.939
-.9r3*r
+.0I1
-.Ar3
-.9A2
-.494
+.119*
-.9s9
+.9L3
+. 108*
-.ss4
+.glg
+ . 9 11
-.9a5
+.492
- .968**
-.962*t
-.595
+.gLg
-.sL6
+.ggl
-.s32
+.062
-.934*
-.s22
+.92r**
-.aLs
-.949*
+.924
+.4I2
-.994
-.995
-.923
+.965
- . g L 9 **
-.939
+.915*
-.9L2
-.933
+.929
-.648**
-.9a3
+ .911
-.sI6
+.928
+.gLO
-.sI2
+.997
-.999
-.A63
- .0I 5**
+.998
+.AO5
.gog
-.997
-.995
-.593
+.992
+ .O9.7
-.9o2
+.O99
-.923
-.aL6
-.962*
-.srB
-.o5r**
-.s6L
+.aIB
-.9r4
+.935
Station
(period
of
recordl)
Rank Statietic
('l)
Coef f icient
Regression
Sumner
l{inter
Annual
(wAsHrNGToN)
gsgS
oL16
s729
ga72
L233
t276
L4A4
L504
I 586
L65g
r665
2595
4154
4486
5801
6939
6096
6r14
5624
6678
67A9
7rgs
7 4AA
7507
7 7 73
7939
8286
8332
8773
893I
Aberdeen (1891-1979)
Anacortes (1893-1979)
Blaine (1894-1979)
Bremerton (f898-19?9)
Cedar Lake (f899-1979)
centralia (189r-r979)
Clearbrook ( f9S3-1979)
cle ElLun(1899-r979)
Colfax I Nl{ (1893-1979)
(189S-1979)
colville
(L9gg-I979)
Conconully
Erlensburg (1893-19791
Kennewick (1895-1979)
Landsburg (1993-1979)
Neah Bay (f884-r979)
odessa (L904-L979)
olga 2sE (I890-r979)
olympia llso AP (f878-f979)
Port Angeles (f879-I979)
Port Townsend (1874-1979)
Pullrnan 2 M{ (f894-I979)
-.946
-.L26*
-.962
+.248r,
+.975
-.r22
-.III
-.992
-.o4t
+.942
-.556
-.gSl
+.975
-.L69
+. r45rr
-.gLe
-.s57
-.135**
-.24q**
-.I44**
-.925
-.979
+.gLg
Rosalia (1892-f979)
wso (I879-1979)
seatrle
-.S51
Sedro tfooley (1897-I979)
Snoqualmie FaIIs ( 1899-1979r+.L2O
-.gOl
Spokane Wso AP (f882-19791
Tacoma City
-.L77**
HaII (1884-1979)
Tatoosh Island
-.r89i*
wB (rs79-1966)
+.OgL
Vancouver 4 NNE (1899-f979)
WaIla walla
wso cr (1873-1979)
(1891-1979)
9012 tfaterville
(L9AO-L979)
9238 wilbut
9465 Yakima WSo AP (1919-1979)
-.298r*
-.9L4
-.944
+. tg8
128
-.a98
-.996
-.g\s
+.924**
-.s73
.ggs
+.996
-.s95
-.942
-.o39*.
-,o24
+.175rr
-.985
+.916
-.944
-.s27
-.422
+.9L3
-.9L4
-.gsa
+.999
+.97I*
+.L47*
.ags
-.9L7
-.957t
-.957"
-.928**
-.a92
-.928*
+.922
- .911
+.987t
-.998
-.934
-.932"
-.sL3
+. l52rr
-.s74
+. gI5
-.959
-.92r
-.oLg
+.ol5
-.srg
+.o92**
-.o44
+.693
-.997
.ggg
.ggg
+.6A4
-.a93
-.966**
-.o58**
-.gga
-.L79*'
+.952t
- .2]lr*
+.949
-.975**
+.9I2
- .gl9*'
-.9r7
-.999
+.9I9
..gLI
-.997
-.962
-.s42
,sgg
-.os2
-.aar
-.as4
-.o95
+.9o5
+.947
+.126*
+.o95
-.aL4
-.oLg
- . o58i
-.047"
-.925*r
-.9s5
-.92L'
+.ggl
+.ggI
-.oL4
-.9s7
+,92',*
-.os3
+.996
+.925
-.0r1
-.9s4
-.as3
-.grg*
-.ss1
6)g/
+
..--i
-__
tfJ
Figure 2I.
Results of Trend Analysis of Long-Term Data
series.
Prus and Minus values are for Lhe Rank-statistic
( see Tabre 6) .
circre
rndicates
significance
of the statistic
at the 9A percent Level; Double Circle at the 95
Percent Level.
129
a two-tailed
with
\,fas evaluated
coef f icients
regression
annual data
F
o
r
Results are included in Table 6.
t-test.
trend'
n
o
n
I
i
n
e
ar
f
o
r
are much the same as those
the results
t
h
e
reof,
l
a
c
k
p
a
t
t
e
r
n
,
o
E
the same
In Oregon essentially
are
t
h
a
t
coefficients
regression
ttrose
Of
exists.
and
g
O
a
r
e
n
e
g
a
t
i
v
e
seven
peicent
levet
at ttre
significant
s
t
a
t
i
o
n
s
t
t
r
e
As with the rank statistic,
sii are positive.
a
s
h
o
w
(
H
e
a
d
w
o
r
k
s
and Detroit)
in the north Oregon Cascades
m
i
x
e
d
'
a
r
e
results
otherwise
trend;
positive
significant
are
ds expected,
data,
for winter
Regression coefficients
i
n
m
ost
to those for the annual series,
similar
unlformly
s
u
n
t
mer
For the
of significance.
cases aC the same level
a
nd
season ttrere is a tendency for negative trends to occur
n
e
g
a
t
i
v
e
(gA percent)
trends are all
the four significant
through the state.
and widely scattered
trend also yields
of linear
In Wastrington the analysis
trend
of non-Iinear
to the analysis
results
nearly identicil
Only
annual trends in most cases.
trends mirror
and wlnter
were found to have significant
ttrree of the sunmer series
two negative and one positive.
regression coefficients,
Short-Period
Fluctuations
to glean
is so difficult
reaaon that it
The principal
there
t
h
a
t
i
s
a
n
a
l
y
s
i
s
t
r
e
n
d
f
r
o
m
i
n
f
b
r
m
a
t
i
o
n
u
s
e
f
u
t
much
o
ccur
t
h
a
t
t
r
e
n
d
s
s
e
r
i
e
s
,
d
a
t
a
t
h
e
w
i
t
h
i
n
f
l
u
c
t
u
a
t
i
o
n
s
are
p
e
r
i
o
d
of
e
n
t
i
r
e
t
t
r
e
t
h
a
n
t
i
m
e
p
e
r
i
o
d
s
o
f
s
h
o
r
t
e
r
over
t
h
e
i
n
f
l
u
c
t
u
a
t
i
o
n
s
t
h
e
s
e
t
o
o
b
s
e
r
v
e
w
a
y
b
e
s
t
T
t
r
e
record.
This has been
data is to simply plot them as a time series.
set of
The entire
stations.
iihe 7-g long-term
done for
these
For
L2 of
E.
in
Appendix
is
collected
graphs
s
e
a
sonal
s
t
a
t
e
s
,
t
w
o
t
h
e
o
v
e
r
d
i
s
t
r
i
b
u
t
e
d
e
v
e
n
l
y
stalions,
(
f
i
g
u
r
e
2
2
)
.
i
n
c
l
u
d
e
d
graphs are
some
in the data series,
Due to the rapid fluctuations
the
a
l
l
o
w
t
o
i
s
n
e
c
e
s
s
a
r
y
t
e
c
h
n
i
q
u
e
of
fiftering
sort
S
m
o
o
tho
s
c
i
l
l
a
t
i
o
n
s
.
l
o
n
g
e
r
p
e
r
i
o
d
to "F"""
investigator
a
i
s
a
v
e
r
a
g
e
s
m
o
v
i
n
g
w
i
t
h
d
a
t
a
t
h
s
o
f
ing,
ot- filtering,
rapid
ttre
attenuate
to
purpose
being
the
common practice,
signifiwittrout
(high-fiequency)
waves in the data series
The
(
I
o
w
f
r
e
q
u
e
n
c
y
c
o
m
p
g
n
e
n
t
s
).
t
t
r
e
s
l
o
w
e
r
affecting
"aasns[u. m
t yp t i o n h e r e i s t h a t t h e h i g h - f r e q u e n c y
are
oscillations
p
a
r
t
i
c
u
l
a
r
n
O
(
i
.
e
.
o
f
o
r
n
o
i
s
e
)
n
a
t
u
r
e
i
n
random
either
e
s
t
i
m
a
t
e
a
n
m
e
r
e
l
y
i
s
v
a
l
u
e
a
Ttrus
"smoothed"
signifiCance.
t
h
e
p
r
e
s
e
n
t
i
n
n
o
t
w
e
r
e
i
f
n
o
i
s
e
b
e
w
o
u
l
d
v
a
l
u
e
of what the
e
x
i
s
t
d
o
o
s
c
i
l
l
a
t
i
o
n
s
l
o
n
g
p
e
r
i
o
d
d
e
f
i
n
e
d
,
series.
If welI
fqrm'
their
in the series the technique can aid in revealing
poorly
are generally
variations
However, long-period
w
h
e
re the
s
e
r
i
e
s
d
a
t
a
p
r
e
c
i
p
i
t
a
t
i
o
n
i
n
p
a
r
t
i
c
u
f
a
r
f
y
defined,
case
t
h
a
t
q
u
i
t
e
L
a
r
g
e
.
I
n
i
s
v
a
r
i
a
t
i
o
n
o
f
random component
i
n
a
p
p
r
o
p
r
i
a
te
i
s
a
v
e
r
a
g
e
(
e
q
u
a
l
w
e
i
g
h
t
e
d
)
m
o
v
i
n
g
an ordinarj,
s
u
c
tt a
i
n
o
s
c
i
l
l
a
t
i
o
n
s
l
o
n
g
p
e
r
i
o
d
e
x
a
g
g
e
r
a
t
e
e
v
L
n
and may
130
Figure
22.
Time Series Graphs of Annua1 (Water Year) and Seasonal
Precipitation
a t 12 Long-Term Stations
in Oregon and
Washington:
Oregon:
Washington:
A3g4
A4L7
2L68
4679
6932
6749
Ashland
BaKer KBKR
Dayville
Lakeview 2 NNW
Newport
Portland
KGW-TV
Aggg
6114
667A
793A
8931
9612
Aberdeen
Olympia WSO AP
Port Townsend
Spokane WSO AP
W a l l a W a l l a W S OC I
:
Waterville
131
0304 A
Annuol
i = 1 9 6 2i n
s= 454in
Winter
,. = 1547 in
o
N
U
!
2 a
-
U
o
z
@
@
132
Annuol
i = ll 32 in
s= 280in
o
@
9
g ! N
o
= 9
o
Winlor
i = 7.00 in.
s = 1.95 in.
$
s
F
3
9
:
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s
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= o
G
o
i
N
o l
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re6a
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aeza
Summer
i=433in
s = 159 in.
N
N
N
o
@
9
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: E f , o
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N
192€
r930
YEAR
r€at
2168 Doyville
N
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Annuol
i = ll 70 in,
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Summer
i =4l 4i n
s = l0l in
4670 lokeview 2 NNW
o
o
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=
S
Winter
i = 10.86 in.
s = 3.61 in
N
@
N
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Q
N
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Summer
i = 373 in.
3=174ill.
135
6032 Newporl
Aonuol
x = 68ll in.
s = 12.93in.
o
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o
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1926
1930
YEAR
6719 PortlondKGW-W
o
@
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6
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O
o
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Winier
i = 3551 in.
s= 873in
0
ts
Q
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9
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--l-aeo--liea
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Summer
x = 693 in.
s=26Oin
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€ t
bza--lteo--raea--GaaisG--ieie-iee@-re.+€----G€a'te@-rtts--ieso
YEAR
137
r-saa
Aberdeen
Annuol
i = 8250 in
s = 1206 in
o
N
o
o
=
e
o
o
@
Q
1
o
g 2@
o
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o
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N
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Winter
i = 69_30in
s = 12.27 in
o
N
o
:
o
9
o
6
o
o
o
N
.s2 o
H o
=
o
o
o
o
N
o
YEAR
Summer
r = l32l in
s=4Olin
@
o
r
N
6
u
;s-
E
o
z
N
o 18Bo
1920
r g3a
YEAR
r38
6114OlvmpioWSOAP
Annuol
i=5120in
s = 10.32in
I
I
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F
t
t
E
E
@
!
6
Hr
= B
c€
c
F
3
o
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Winter
i = 4!.@ in.
s = l03l in.
R
C
t
t
E
E
6
!
6
E +
= B
B
E
R
I
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fl
F
3
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g
te70
Summer
i = 7.61 in.
s = 2]9 in.
leaa
6678 Port Townsend
Annuol
i = 19.24in
s=380in
o
@
N
o
@
N
N
g l €
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o
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s
@
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o
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Winter
r = 1 3 6 5i n
s = 307 in
-
@
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N
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laa@
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189A
tgoo
1916
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tg30
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I ssa
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YEAR
Summer
t = 5.59 in
s=2l0in
Q
@
@
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! 2 e
=
=
o
@
140
tg70
r 966
7938 SpokoneWSOAP
@
o
t
t
3
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122
Winter
i = 11.49in.
s = 309 in
o
r
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T
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o rESo
raso
lsoo
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tg26
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rgso
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YEAR
Summar
t = 458 in.
s = 1 . 8 2i n
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w
faSa
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r89a
tgao
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lg20
ts36
YEAR
r4l
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1954
r.s6g
1970
rga6
Annuol
i = 1 6 1 3i n
s= 3l8in
o
N
I
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2
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Winter
i = ll 85 in
s = 289 in
t
F
F
9
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I
a
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f950
1066
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YEAR
Sumner
i = 128 in.
s = 171 in-
:
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fi
= o
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o
o t
142
teao
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N
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r = 7.85 in,
s=2./4id
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N
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3
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YEAR
@
N
e
@
@
N
o i
way that
they appear as prominent
cycles
or quasi-cycles.
the
tendency
Known as
effect,
this
can
Slutzky-Yule
physical
introduce
apparent
cycles
have
no
which
significance.
unfortunate
result
may be
the
Anottrer
displacement of peaks and troughs in the time series.
Early
climatological
unaware of these
hunters"
were often
"cycle
pitfalls,
perpetuating
thus
myths
non-existent
of
(nottoway
periodicites
in
ctimatic
data
Mitche1l
1958,
1964) ,
by
undesirable
be
These
effects
can
eliminated
modifying
the weights
more
in a moving average to create
accurate response characteristics.
One standard approach is
proportional
a
to
set
the weights
the
of
to
ordinates
(normal)
probability
a
nine-term
curve.
For
Gaussian
weighted moving average the weights are as follows:
weight
number
weight
.gL
.95
.L2
.29
.24
.29
.L2
.95
.6L
xi-4
*i-3
* r-2
*i-1
xi
x.;iI
x i+2
xi+3
xi+4
is
average is used because it
This form of weighted
relatively
easy to interpret
while
capable of emphasizing
a
the form of any oscillations.
is essentially
The filter
p
a
s
s
"
t
o
filter
which allows tow frequency oscillations
"Iohr
those at
emerge unchanged while
attenuating
or eliminating
f
r
e
q
u
e
n
c
i
e
s
.
higher
a
The graphs of Appendix E and of Figure L2 represent
a
m
o
u
n
t
t
o
massive
of
data
for
which
it.
is
difficult
generalize
must necessarily
and much of the interpretation
be left
to the reader.
approach here is to
The simplest
discuss
the data
in
the
and western
context
of
eastern
by the
and western Washington (divided
Oregon and eastern
crest of the Cascades) as they are arranged in Appendix E.
Western
Oregon
record
The longest
Iength
is that
of Astoria
WSO AP
( 1854-f979),
which includes
data from Fort Stevens for the
years 1877-1883.
that
strould be
An important
observation
made initiatty
rapidly.
is that the series oscillates
There
marked
is
littte
evidence
of
extended periods
of either
dryness or of marked wetness,
in
to
contrast
Granger's
(tglt )
lowland
precipitation
findings
for
in
annual
years
periods
of
a
f ew
strort
California.
Only
144
significantly
above or below the long-term
mean can be
identified
as
follows z
period;
\r/as a dry
I92g-193I
I932-L935 was a wet period as was f879-188I.
Otherwise the
extreme years tend to occur in isolation.
The moving-average
line
for the Astoria
series reveals
many short-term
trends,
up to about
duration.
46-yeats
There is an upward trend from the 1850s to the early t8g0s,
highlighted
by the wettest
year on record,
LB76 (l-Lz,82
inches,
L48 percent
of the long-term
mean).
The years
1882-f892 were quite
dry.
Beginning in the wet period of
the I89Os there was a downward trend to the early
L936s,
highlighted
by the driest
year on record,
L928 (43.35
yet even during
inctres, 57 percent of the long-term mean).
period
this
precipitation
of
decreasing
there
were
oscillations
and some very wet years, specifically
1916 and
I92L.
Immediately
following
the dry years around I93A were
the very wet years of the mid-I930s.
From the period of
relative
wetness in the I95As to the present,
then, was a
gradual decrease in annual precipitation.
Certainly
any statement ,as to long-term
trend in this
data series has Iittle
meaning.
trends exist
Short-period
but vary in duration
and magnitude.
There is a temptation
in time-series
analysis
of this
type to look for cyclical
behavior
that might have some predictive
value.
Spectral
analysis
is a statistical
technique commonly used to detect
periodicities
and such analysis
has been reserved
for
a
subsequent
study.
However, visual
observations
of
the
weighted-average
line
suggests that for much of the record
there is an approximate 2T-year period oscillation
from one
dry period
to another or from one wet period
a
nother,
to
perhaps related
to the 22-year HaIe sunspot cycle thought
to exist
in climatic
series
in the western two-thirds
of
(tnlitctrelL
the
United
States
1-97g).
Without
further
analysis
it
would be inappropriate
to corunent further
on
the cycle in this report.
At the other
stations
on the Oregon coast
the same
generar
pattern
exists
as at Astoria
arthough
ttrere are
some interesting
differences.
At Newport simirar
rhythmic
oscillation
between wetter and drier periods occurs, but it
courd also be said that the period
from the L93as to the
l976s was one of an upward trend,
€rt least
through
the
early L97As. At Bandon 2 NNE this same pattern
is clear,
a
downward trend
from the r9gas to the r93as forrowed
by an
upward trend from the L93as to the r97as.
Another cautious
reference
to cyclicar
behavior wourd suggest tl-e so-called
Greissberg cycle of about 88 years (agee LgBa).
An anomaly
at Bandon is the sequence of three
extremely
wet years,
1893-1895, the latter
two each receiving
I85 percent of the
Iong-term normal.
145
series again show the
In the Willarnette
Va11ey, station
pattern
general
trend from the L89As to the
of decreasing
of
from the I93As to the early
trend
L93As and increasing
clear at
mid I976s,
The early century trend is particularly
stations
Univ. and Albany and at the
such as Corvallis-State
Pasg
stations
of southwestern
Oregon; for example, Gfagts
in
a downward trend
others
and Roseburg KOEN. At several
the
but
part
apparent,
is less
the early
the record
of
Stations
trend in the latter
increasing
half is consistent.
the
in the I96As but reflect
in the Cascades begin
only
at similar
latitudes.
trends of valley
stations
short-term
that
it
can be said
For western
Oregon in general
series exhibit:
annual rainfall
from year to year;
a) rapid oscillations
b) very few grouping of unusually wet or dry years;
trend from the I89Os to the 1930s, more
c) a decreasing
so in the southern half of the state;
from the early
trend
L93As to the
d) an increasing
early or mid L97As.
Eastern
Oregon
in
series
made for the precipitation
The observations
Heppner
western Oregon are true in parL for eastern Oregonr
in north central
Oregon and Lakeview 2 NNW in south central
point
for discussion.
During the dry
serve as a starting
yearF
a
o
f
several
period
t
h
e
r
e
w
a
s
s
e
q
u
e
n
c
e
t
h
e
of
I93Os
a
p
p
r
o
x
i
m
a
tely
I
o
n
g
t
e
r
m
m
e
a
n
,
d
t
H
e
p
p
n
e
r
t
h
e
welI
below
approximately
Indeed
and
at
1928-1934.
Lakeview
L928-L937
was
period
from about
entire
L9L4-L934
at
the
Lakeview
a
lso
y
e
a
r
s
w
e
r
e
t
h
e
dry.
19O8-19I1
unusually
At Heppner
the
e
a
s
t
e
r
n
m
o
s
t
o
f
O
r
e
g
o
n
dry.
consistently
Throughout
p
a
rt
p
r
o
l
o
n
g
e
d
i
n
t
h
e
w
e
s
t
g
r
n
p
e
r
i
o
d
t
h
a
n
was more
1930s dry
y
e
a
r
s
m
o
r
e
o
b
v
i
o
u
s
a
r
e
a
l
s
o
of the state.
Sequences of wet
than in western Oregon.
from the I89As tp about
downward trend
The prevailing
I93A is seen in most of the series as is the recovy from the
since
However the upward trend
L976s.
1936s to the early
the
a
n
d
decade
in the following
the 193Os occurred primarily
a
l
t
t
r
o
u
gh
is fairly
line
steady since then,
weighted-average
l
a
r
g
e
.
fluctuations
about the mean have been
interannual
a gqod example of this pattern'
Burns WSO cI provides
western Oregon, and the downward
The L89As were dry, unlike
from the L96As into the I93gF.
The year L9A6
trend existed
(
1
9
.
9
8
p
e
l:cent of the
inches, 183
was the vrettest on record
p
e
r
i
o
d
was rapid in
Recovery from this dry
Iong-term mean),
t
h
e
r
n
i
d
I976s there
the 1936s and 194Os and from then until
a very
exhibits
Wasco
no trend
upward or downward.
is
p
e
riods.
o
r
dry
wet
steady annual series with no distinctly
upward
a
n
Oregon
of Weston in northeastern
In eontrast,
146
yet at
trend from the 193Os to the I976s is clearly
noted.
Pendleton
WSO AP, also
in
northeast
the
Oregon, while
decade of the I93As is also quite dty, there are several
years in the subsequent decades just
as dry (e.g.
i-9732
7.23 inches, 55 percent of the long-term mean) and there is
certainly
no increasing
trend from the t930s to L97As.
At
Baker KBKR, the steady downward trend from LA9O to I93g is
also very clear.
For the eastern half
of Oregon, thenr generdlizations
are more difficult.
The only consj-stent
feature
is the
drought of the 1930s which was longer in duration
than in
western Oregon.
Western Washington
Certain
aspects of the general
pattern
found in the
precipitation
time series
for Oregon are also to be found
for
those
in Washington.
The I896s were relatively
wet
throughout
the state
and there was a downward trend
from
then untir
about r93a,
folrowed
by a quick
recovery
to
normal amounts in the early
r93os.
The ensuing decades
sttow very
Iittle
uniformity
over
large
regions
of
the
state.
Port Angeles and Port Townsend, two stations
in close
proximity
on the north
coast
of
the Olympic peninsula,
serve as a useful starting
point for a discussion
of time
series
in western washington.
At port
rownsend Lg3g was
the drj-est year on record and a very precise
point
turning
between the downward trend since the L89as and a subsequent
upward trend
lasting
until
about
this
I97A.
However,
period
latter
of increasing
annuar precipitation
did not
occur
at Port
Angeles.
there
Instead
was a small but
steady decrine beginning
in the late r94as and extending to
L979.
The difference
in these two locales
assumed to be
under the same combination of ctimatic
controls
is furttrer
indication
of
the
danger
general izing
in
trends
and
fructuations
in a region of such great spatial
variabirity.
On the far
norttrwest
coast
at Neah Bay and Tatoosh
rsrand there \rrere severar very wet years between rB85 and
1992.
This was the wettest
period
on record
at Tatoosh
(through
Islanil
L966) and at Neatr Bay only three very wet
years in the r976s exceed the values of the wet l89os.
rn
L9g3 annuar precipitation
decreased drasticarry
and, with
the exception
of a coupre of average years in the rg2gs,
remained very tow through r93a.
rf there is any trend at
arr during this period it is srightty
upward from rga2 to
L93a, again a contrast
to this same period at port rownsend
and Port Angeles.
At Neah Bay an upward trend continues
to
the present"
A
between
distinct
lack
of
correlation
Neah Bay and Aberdeen, ttre other
147
also
apparent
is
Washington coastal
a decrease
Aberdeen experienced
Neatr Balr
Unlike
-from
station.
of
series
T
h
e
t
o
L
g
3
g
.
L
,
A
A
in annual precipitation
is
there
at
Aberdeen
but
stations
at both
wet years occurrLd
years;
4A
the
last
over
trend
of an upward
no i-ndication
the- L94As and since
through
ttrere was an increase
rather
'
va'Iue
steadY mean
then a fairlY
Periodsofwetyearsanddryyearsarecertainlytot
for
At' Neah Balr
Washing€on,.
western
throughout
unifonm
-:
i
d
e
n
t
i
f
i
e
d
b
e
c
a
n
:
p
e
r
i
o
d
s
d
r
y
distinct
thre6
example,
Each one
Lgg4-LgL2, Igiz-Lg3A , and 1936-19'39.
apprlximatellr
s
t
ations ''
a
t
o
t
h
e
r
m
a
g
n
i
.
t
u
d
e
i
n
considerabty
of these varies
at
found'
be
to
not
is
parLicrllar
The ea.rtrier of Lhe three in
a
nd
e
x
t
e
n
s
i
v
e
m
o
r
e
w
e
r
e
t
w
o
The' Iatter
locations.
several
years
in
wet
very
of
series
a
in gerreral we,re separated by
the early L936s.
withinthePugetLowlandthereisafairlyhighdegree
At Tacorna,
patterns-.'
in a-nnual precipitation
uniformity
of
to:
ttre
I896s
f
rom
e:<,ample, the common downward trend
for
only
the
were
yeairs
]929-1939
The
l.g'gg1 Occurired,.
entir'e
the
for
normal
y
below
aecid6af
consecutive
1'""t"
decades;
four
past
Over the
1884- Lg7't .
of retord,
period
c
l
e
ar trend one way or another
n
o
e
s
s
e
n
t
i
a
l
t
l
r
b
e
e
n
h
a
s
there
more ttran a few Years,
Iasting
are geen at (
overall
Pattern
the existence of
particularlY
th'e d:
a't Blaine
nortn*
To the
\'
extreme
ttt'e
However
o,ccur .
" extremely
in
1934
cuLninating
w
et years
t
h
r
e
e
striking,
(5g.44 inches, L46Z of normal) '
to the easL side of tlile
for those stations
Time series
and
Landsburg,,
(Clearbrook,
Sedro Wooley,
puget
Lowland
ternperal"
their
same in
S"n5quafmi-e FatIs ) are much the
middtr'e
sltow tlre wet years of tl"
AII dramatically
patt-ern.
after'
a
n
d
befone
imnrediatety
periodJ
dry
1930s with
middle
ttre
t'o
the middtr e I94As
for
v-af uls
ei."ipitation
nor ileereasi'ng'
increasing
neittrer
quite
steady,
\rere
I976s
decline in the late L976s'
and show a distinct
Eastern
Washington
ttrat were noted between western
Many of the contrasts
and eastern
between western
Oregon alSO exist
and eastefn
as a
s
e
rves
located'
centrally
Walerville,
Wastrington.
w
i
d
e
s
p
read
Here the fairly
for discussion.
polnt
;G;ai;g
1
8
9
6
s to
t
t
r
e
from
annual precipitation
trend of decreasing
in a sequence of three very
about Ig3A is seen, culminating
dryyearslg2g-1931.Through!h"tlllsandL946stherewas
year on
which peaked in L948, the wettest
an- u-pward trend
mean) '
of the long-term
(23.84 inctres , 2L5 percent
record
mean
the
about
Since about LgSg there have been fluctuations
evidence of an upward or downward trend.
but little
148
The
to
1899s
downward trend
L93g
is
a
fairly
persistent
feature
throughout
eastern
washington
as seen
from the ottrer precipitation
series.
Exceptions
may be
noted for odessa and yakima wso Ap.
Also with onry minor
exceptions
the years L929-r931 were the most extensive
dry
period
on record.
By L94O there was a return
to average
precipitation
throughout
eastern
washington.
An upward
trend from L94g to the r976s, observed for many rocares in
oregon, is found nowhere in eastern washington.
rn general
there has b-een a fairly
constant
mean value over the last
4A years.
Some stations
experienced
a dry period
in the
early
I956s,
coincident
with widespread drought
in other
parts of the country,
and in the middre l96as.
The rongest
record presented
for eastern
washington
is that
of walla
walrs wso cr.
There the Aa-year period
from rg4g to rgTg
is
remarkabre
for
its
consistency
when compared to
the
entire period of record.
A third
method of evaluating
changes over time is to
calculate
basic
statistics
for
periods
ten-year
and to
compare each period
to
the
period
entire
of
record.
rnstead of or in addition
to an inconstancy of the mean, a
crimatic
fluctuation
may also consist
of a change in the
overarr
variabirity.
Therefore,
decadal means and standard
deviations
were carcurated
for alr
rong-term
stations
and
data for about harf the stations
are presented in Table 7.
The statistical
significance
of changes in the mean
(ttrat
is,
whether or not the decadar value
is different
than the rong-term value) was determined by using cramer's
( tvtitcherl
test
et ar 1966 ) ; for changes in the standard
deviation,
the F-ratio
test was used (Cregory 1973 ).
These
two tests are described briefly
as follows:
(a)
To apply
Cramer's
test
x and s are defined
respecLively
as the mean and standard
deviation
of
the
entire
series of n years.
Further,
x.L.is defined as the
decadal (lO-year)
mean to be compared wlth x.
Then:
(e)
The student's
t-statistic
with
(n-2)
degrees of
freedom is
calculated:
tt
n-2)
Tk
(M)
149
Table
7
Mean and
of
Variabitity
Statistics
Decadal
at
Compared to Long-Term StatisLics
Deviation),
*value
**Value
significant
significant
at 90 percent
at 95 percent
150
level
level
(Standard
g
36 taLigns.
WESTERN OREGON
Bandon
Ashland
s
f
x
s
r3.
5 7. 5 8
4.54
term
2 NNE
Corvallis-St.
Univ.
E
s
4A.46
7,79
L97Os
- 19.95
+
4.84
+ 59.13
+ 14.58
+ 45.99**
+ 13.95*r
L96Os
- 17.92
+
5.1I
+ 58.15
-
8.77*
+ 49.96
-
6.60
L95Qs
+ 19.63
+
6.35**
+ 65.39*
-
9.72
+ 4I .67
-
6.57
L94Os
+ 22.94*
-
3.66
- 55.47
-
9.57*
- 35.79**
-
6.46
I93Os
- I8.I8
-
3.88
-
46.49**
- L2.29
- 36.23*
-
7.38
1926s
- 18.61
+
5.85*
-
47.73r*
- 1 3. 5 3
- 38.1r
+
8.17
19I0s
+ 19.85
-
2.5rrf
- 52.85
'
9 .39*
+ 4I.59
-
6.84
19OQs
+ 2l .23
-
3.79
- 57.4L
-
8.79*
+ 43.64
-
4.95**
I89Os
+ L9.72
+
4.63
+ 73.26t*
+ 23.56**
+ 4L.97
-
7.28
I886s
+ 2Q.q5
+
5.96*
+ 58.48
- L5.25
Grants
Pass
x
s
39.34
L97Os
+ 59.67*t
L96As
Headworks PtId.
8.qL
W. B.
x
89.59
r3.87
+ Lg.4g*
+ 82.97
?
+ 32.L9
-
+ 89.72
-
8.75
+ 34.82*
+ Lg.54i
+ 96.55**
- 13.42
- 38.94
I .35
3S.AS
-
7.q2
+ 84.62
+ I7 .7q
193@s
- 3 6 .r 5
7.48
2 7. L 6
+
9.42
+ 83.17
+ 2r.95*r
L920s
-
36.69
8.99
24.68t*
+
9.96
- ?3 .15.**
- 12.42
l9lgs
-
38.27
8.s5
28.05
-
4.39**
- 77.t6
- rr.41
19OOs
-
39.60
5 .52**
+ 34.52r
-
6.59
- 75.35r
-
1890s
- 37.98
( n=9)
5..62**
+ 3L.45
+
8.52
15.69*r
39.26
+ 44.26
5.95**
195Qa
+ 44.99
L9Ags
r5t
4.88**
!
I
. J J
8.q9*
9.97*
Portland
-term
KGW-TV
s
E
s
L2.93
42.43
8.88
32.59
7_,p
L97Aa
+ 72.74
+ L7.23*
+ 44.83
+ 1 2. 3 5 r *
- 3I :23
+ LA.28t
I96gs
+ 75.36*
- 12.85
+ 44.74
-
5.84*
- 31.28
-
5.46
1950s
+ 75.42*
-
9.7r
+ 44.44
-
?.95
+ 36.56*
+
8.12
1946s
- 5 7. 7 7 * t
-
7 .58**
-
39.97
-
8.49
- 32.5L
-
6.O9
I93Os
- 58.92rr
+ 1 3. 2 I
- 38.48
-
7.38
- 28.73*
-
6.58
L92gs
- 64.36
+ 13.59
- 36.91**
-
7.89
- 28.92*
+
9.22
19tgs
+ 68.49
+ 14.73
- 39.84
-
7.76
- 30.43
-
5.6e
1966s
+ 69.61
-
- 40.43
-
3.62**
+ 33.33
-
4.24
l89Os
+ 79.99
- rs.o7
-
-
6.58
+ 37,96**
-
6.L4
+ 3 4 .1 3
-
6.Sa
8.66*
39.96
1886s
+ 46.88r
+ 11.98*
1876s
+ 52.44t*
(n=B)
+ 1I.25
EASTERN OREGON
BaKer
x
KBKR
Burns
x
s
II.32
WSO CI
Condon
s
x
.r7
.74
s
3 ,s 5
197Os
+ 1 2 .1 5
3.24
- rg.a2
3.69
+ L4.69
3.22
1969s
- L9.27
I .75**
+ 1I.95
2:87
+ 13:19
4.2r
1950s
+ 1I.97
3.66*
+ I2.2L
2.67
+ 13;82
2.8r
L94As
- LL.g7
2.64
+ I2.Ig
2.67
+ 1 2. 9 8
4.99
1930s
-
2.24
-
7.97**
2.Ag
-
lg.9g*
2.43
L92Os
- rs.g9
1.85*
-
9.86
4.56
+ 1 3. 0 3
2.7e
I9I6s
- r1 .31
3.t6
-
IS.BA
1.gg**
- l1;86
2.4e
L9OOs
+ 11i98
I .68**
+ I2 .51*
3.97
1890s
+ 1 3. 9 0 r r
3.2L
-
2.44
9. r7**
9.33*
(n=7)
152
DaWille
;
Fremont
a
I.7g
a
.46
2.89
4.47
L97gs
- LL.4g
2.62
+ 1 1. 5 8
3.r9
+ 31.24
+ Lg.gg
L96Oe
- 11.39
2.80
+ L9.76
4.L2
- 39.63
-
5.15rr
L95Oa
+ L2.82
4.gL*.
+ 1 2. 3 6
5.44t*
- 3s.64
-
5.89t
L94Oa
+ L2.26
4.23**
+ ll.ot
1.73**
- 29.44
-
7.99
1939e
- LO.56
1.89*
-
9.38
2.s5
- 26.63.
-
5.26r*
L92Oe
- rr.67
3.65
-
9.25
3.67
- 27.57
-
7.35
l9lOs
- LL.3g
2.?L
-
4.74
2.38r
- 27.32
+
8.95
L96Oe
+ L2.92
2.45
+ 32.25
-
6.57
189Os
+ L2.L4
r .57*r
+ 42.32rt
+ LL.22r
+ 34.46
(n=5)
+
I88Os
Lakeview
-term
Prinevil
Ie
9.98
Wallowa
x
s
14.58
4.5
9.47
2.42
L7.
2.47
+ L7.75
4.35
x
s
x
L97Os
+ 15.44
+
4.75
9.92
L966s
+ 15.84
+
4.66
9.80
+
2 . 72
- r7.49
2.98
I95Os
+ 1 5. 9 8
3.92
L9.93*
+
3.35*r
+ 19.51*
3.3r
1946s
+ 15.48
3.45
r9.25
2.55
+ 18.54
3 -44
I93Os
- Ll .72**
3.92
8.3I
I .86
- 15.86
2.78
L92Os
- r1.gli*
3.38
8.78
2.66
- L6.so
4.72
I9I6s
- 11.81*r
2.48**
9.ga
2.49
+ 17.82
4,01
L96Os
+ L7.95*
4.62
9.95
1 . lg**
- 16.89
(n=6)
3 .7-?
I89Os
+ L7.92*
4.77
I886s
- L4
"47
(n*5)
2.72**
153
WESTERN WASHINGTON
x
-term
x
5
49,
L2.
.56
Centralia
Blaine
Aberdeen
x
s
45.49
7.8r
- 90.65
19.93**
- 39.37
9.65**
+ 46.95
rI .38*
L97Os
+ 83.13
9.39
+ 42.64
6.76
+ 47.96
4.97t
L966s
L95Os
+ 94.9A
L2.64
- 39.29
6.32
+ 47.68
L946s
- 75.87*
L5.35
-
6.3r
- 41.38*
+ 89.64*
+ 15.57*
+ 44.42*
+
9.37*
- 45.92
+
9.Og
I9 36s
- 79.26t
+ L3.64
- 36.56**
+
7.7t
-
+
I .41
L92gs
I9lOs
- a9.43
Ls.7g
+ 4t .59
5.54
+ 47.42
196@s
+ 87.66
I .87
+ 4L.5A
(n=7)
3.r3**
+ 46.9I
+ 85.21
8 .r r *
+ 44.58*
(n=5)
?.19
-
1896s
-
37.96
OIga
x
-term
2L.32
.13
+
42.87
44.A7
+
8.45
6.79
+ L9.63'
).oz
-
6.43
2 SE
s
51.
4.92
I976s
+ Lg3.L2*
+ 33.29*,
- 29.04
7 .97**
- 59.89
+ 14.32*
1960s
+ t95,72*t
- l7 .16
+ 39.94
4.56
- 51.]7
-
L95Os
+ L92.78*
-
+ 39.L3
4.L7
+ 5 3 .1 5
+ II .6q
L946s
-
86.87
- 12.16**
- 27.28
5 .48
-
-
8,48
I9 30s
-
85.23
+ 22.78
- 27.8L
4.49
+ 53.35
-
9.60
I926s
-
75.64*t
- ro.99**
- 26.96*
5.92
-
-
9.24
I9 IOs
-
74 , 6 A * *
-
+ 3I .24
4.4L
+ 52.42
-
9.33
L9EOs
-
a4.96
+ 24.53
+ 29.49
4.31
+ 56.8r*
-
5,92
I89Os
+ l-gg.go**
- 16.56
+ 31.30
5.95
+ 52.98
-
9.39
1886s
+
- 19.35
- 49.56
+ rr .67
99.99
(n=5)
L2.82**
9.26**
154
41.26**
45.44t
6.23*
-term
7.L
58.
5.54
L976s
- 23.53
6 .14
+ 61.49
+ 16.6r*r
- 36.41
8.23
I960s
+ 25.77
3.64
+ 51.55
-
8.93
- 36.94
4.84*
1956s
+ 27.LL
5.54
+ 62.6L
-
9.72
- 37.69
I .61
1946s
- 22.L9**
5.46
- 57.9A
+ 12.Og
- 3 6. 5 3
6.86
193Os
- 22.L9.,
3.42t
- 56.79
+ 16.68
- 3 7. 1 3
e.25
L926s
- 22.AL*r
4.33
- 52.62*
-
6.37*
- 31.68**
5.64
1910s
+ 26.IO
5.25
- 54.74
-
8.O4
+ 38.78
6.33
L9Ags
+ 26.37
3.32'
- 57.85
-
9.22
+ 43.62**
6.15
L89Os
+ 29.73**
4.35
+ 44.49**
5 .88
1886s
+ 29.7o**
3.65
+ 38.52
(n=5)
5.76
EASTER.LIWASHINGTON
CIe
Eltan
Colvil
Ie
Conconully
x
-term
x
s
t .9
L 9 7A s
+ 23.98
9.71**
+ I7.34
4.62*
-
14.31
5 ;47*
L96Os
- 22.33
3.gg**
+ L8.96
3 .48
- 1 3. 7 r
2.67,
1950s
+ 2 3. 5 5
7 .92*t
+ L5.72
1.63**
+ 15.98
2.95
194Os
- 20.97
5.66
-
L6.27
4.52*
+ 16.36
6.96**
1936s
- 29.27
2.34**
-
13.95**
2.4r
- 13.45
5 . 9 4 **
192gs
- 22.LL
5.69
- t5. 13
+
4.go
- L2.77
3.44
1916s
+ 24.L2
5.15
-
+
3.62
+ 1.5.38
3.47
19Obs
+ 24,62
4.7A
+ 18.13
2.35*
+ 16.46
2.r3**
15.91
155
Odessa
Kennewick
x
s
.r3
9.
.63
4.2s
L970s
7 .54
2.L9
-
9.34
2.65
+ 2q.87
4.:15
I95gs
7.O5
2.48
-
9.45
2.gg
+ 2L.48
3.92
195@s
7.72
r.7g
+ IO.57
2.69
+ 2L.55
5.5q*
194gs
g .61**
3.28i*
+ L2,gO'*
4.48**
- L9.57
4.51
l93Os
6 .14r
L.27**
-
8.94
1.87
- 18.98
3.22
L92gs
7 .69
I .87
-
9.r3
2.79
- 19"33
5.?4
19I0s
7 .89
2,L4
+ Lq.24
I .59**
- 1 . 9. 9 2
3,24
1900s
6.39
2.A5
-
].38r*
+ 22.98
4.32
L896a
5.3s
r .65
+ 22.84*
3.95
9.51
(n=6)
(n=5J
Walla
Walla
Yakima
wSO CI
x
x
-term
6.O8
7.36
16.13
3.7
wSO AP
.t
7.44
3 . 0 5 **
+
7.42
t,7g
+
8 .89t*
2.52
2.97
?.81
r.92
r 3 .47r*
I .52**
6 .38
1'9l
L5.O6
3.65
6.5s
1,59
2.63
+ 16,24
2.72
6.97
2.Og
+ I6 .7I
2.87
+ 16.74
3.18
1896s
+ I7 .92*
3.8s
+ I7.99*
3.62
1880s
+ 18.56**
3.22
+ I7 ,75*
2.7t
-
6. l4**
L97 As
+ L6.42
4.45
+ 16.I5
3.46
1968s
+ L5.41
2.99
-
L'.OO
2.95
1950s
+ 18.94*
2.68
+ 16.45
2.72
1946s
+ 1 7. 5 2
5.r5*
+ L6.52
1930s
- L2.32**
2,2L**
-
L92gs
- 13.44**
3.83
-
1916s
- 14,3s
1966s
I876s
15.99
1n=6)
155
The resulting
value of tk is then tested
for significance
at the 9A percent and 95 iiercent levels
of confidence.
(b) The F-ratio
test
involves
a comparison of
v a r i a n c e ( s 2 ) of two data series of different
lengths.
formula used i s :
the
The
(rr)
f =
The value
of
then
referred
F is
to
a table
of
the
F-distribution
and the significance
of the ratio
determined
at the appropriate
leveI
of
confidence.
These data as
presented in Table 7 are summarized below for each decade.
L97As
Western Oregon.
throughout
the Willamette
Stations
vaIIe@oastal
area
received
above
average
precipitation,
significantly
in the mid-WillametLe
Valley
where Corvallis
and Eugene experienced
their wettest decade
on record.
In southwestern
Oregon (Ashtand,
Grants pass
and Roseburg) precipitation
was slightly
below average.
Precipitation
in
the
decade
of
the
L97As was
undeniably
the most variable
on record.
AII
stations
experienced greater
than normal variability
and at most of
these the departures are statistically
significant,
half of
them at the 95 percent level.
Eastern qlegqn.
at most stations
Precipitation
was
above@
average.
However, none of these values
are significant
and at two stations,
Burns and Dayville,
the
decadal
average
is
stightly
below
that
for
the
long-term.
Al-though variability
greater than normal
was generally
for most of the region,
it was not dramatically
so as in
western
Oregon.
fact,
fn
Ert
in
Dayville
Fremont
variability
was less than normal.
precipitation
Western WasJrington.
was slightly
below
averaffiy
of stations.
However, the only
decadal value significantly
different
from its average was
Neatr Bay wtrere it was wetter
than average.
As in
western
Oregon precipitation
was the
most
variable
of any decade on record.
Values were welt above
averge at all stations,
significantly
so at all but Tacoma.
157
Eastern
averaffi
others.
the
statistically
above
\rtas slightlly
Precipitation
at
near average
and very
of stations
are
values
of decadal
None of the departures
significant.
washington.
well
valueg
on record,
highest
its
reached
Variability
the
of these
hatf
At about
stations.
at aII
above normal
significant.
are statistically
departures
L96As
above
generally
was
Precipitation
western oregon.
in
and
Roseburg
at
Ashland
except
everffi-ere
average
the L97As none of these
southwest Oregon.
However, unlike
and only at
level
at the 95 percent
values are significant
Newport for the 90 percent level.
during
consistent
were extremely
totals
Precipitation
of Ash1and, precipitation
With the exception
the decade.
the values
was below normal,
at all
stations
variability
with the
The contrast
at the majority.
being significant
j
s
s
t
r
i
k
i
n
g
.
L97As
average
near
was
Precipitation
Eastern Oregon.
being
s
t
a
t
i
o
n
s
t
h
e
h
a
l
f
a
b
o
u
t
throu@gion,
A
t no
b
e
l
o
w
.
s
l
i
g
h
t
l
y
h
a
l
f
a
n
d
a
v
e
r
a
g
e
above
slightly
s
t
a
t
i
s
t
i
c
a
l
l
y
a
v
e
r
a
g
e
f
r
o
m
d
e
p
a
r
t
u
r
e
s
t
h
e
stations
were
s ignificant.
About
pattern
of variability.
There is no consistent
h
a
l
f
show
a
b
o
u
t
a
n
d
v
a
r
i
a
b
i
l
i
t
y
h
i
g
h
show
ttre stations
half
and
a
t
B
a
k
e
r
s
i
g
n
i
f
i
c
a
n
t
a
r
e
s
t
a
t
i
s
t
i
c
a
l
l
y
Iow.
Low values
i
s
s
i
g
n
i
f
i
c
a
n
t
.
v
a
l
u
e
a
t
C
o
n
d
o
n
t
t
r
e
h
i
g
h
Hood River;
was above average
Precipitation
Western Washington.
Bay was the only
Neah
Again,
every@coma.
its
e
xperiencing
d
e
p
a
r
t
u
r
e
,
a
s
i
g
n
i
f
i
c
a
n
t
station
with
t
h
e
s
i
n
c
e
L
8
9
A
s
.
wettest
decade
western
as in
region
the
typifies
Low variability
a
verage,
a
r
e
b
e
l
o
w
t
h
e
v
a
l
u
e
s
stations
At all
Oregon.
l
o
w
l
a
nd
t
h
e
i
n
t
t
r
e
s
e
P
u
g
e
t
o
f
at three
significantly
a
n
d
Tacoma.
Centralia,
Olympia
near
The decade was generally
Eastern washington.
s
l
i
g
h
tly
r
e
c
o
r
d
i
n
g
t
h
e
s
t
a
t
i
o
n
s
avera@If
no
I
n
b
e
l
o
w
.
s
l
i
g
h
t
l
y
p
r
e
c
i
p
i
t
a
t
i
o
n
a
n
d
h
a
l
f
above averge
s
i
g
n
i
f
i
c
a
n
t
.
from the average
case are the departures
Howev'er,
is dominant in the region.
Low variability
averge
t
h
a
n
h
i
g
h
e
r
h
a
d
and Kennewick
Colville
two stations,
only
t
h
e
i
s
at
Colville
value
variability.
The low
value.
significant
158
L956s
of
Ashland all
With the exception
Western Oregon.
statiffiavera9eprecipitation,si9nificantIyso
at several.
At Headworks, Newport, Roseburg, and Bandon it
and was the
century
decade of the twentieth
was the wettest
western
the
1880s in
most uniformly
wet decade since
Oregon.
values
of
low
region
of
the
most
Throughout
In
none of
these
significant.
found,
are
variability
Oregon
of
southwestern
three
stations
the
contrast,
high
(Ashtand,
show very
and
Roseburg)
Pass,
Grants
at
record
values
on
decadal
highest
variability,
the
Ashland and Grants Pass.
wet
uniformly
most
was the
This
Eastern Oregon.
as it was in the western
century
decadffitieth
half of the state.
With the exception of Hood River E. S.
precipitation,
average
show
welI-above
aII
stations
and Wallowa.
at Prineville
significant
in the region show low variability
HaI f t h e s t a t i o n s
.
variability
However , ttre high
hal f high
and the
other
not.
At
are
low values
and the
values
are
significant
decade
for
the
variability
and Prineville
Baker,
Fremont
second
it
was the
at
Fremont
highest
on recordt
was the
highest
decadal
value
on record.
above
was generally
Western Washington.
Precipitation
but only
avera@tion
of Tacoma and Blaine,
above average.
The
at Neah Bay was the value significantly
t
h
e
pattern
a
s
i
n
t
h
e
s
a
m
e
L
9
6
A
s
.
then was essentially
half
about
with
was unremarkable
Variability
at
v
a
l
u
e
stations
showing below normal.
OnIy the low
significant.
Bay is statistically
the
Neah
Eastern Washington.
T h i s w a s t h e only decade in which
At
alI
stations
experienced
above averge precipitation.
are
values
the
and
two
of
these,
Spokane
Yakima,
decade of
its
wetLest
significant
and Yakima experienced
the century.
the departure
below normal,
was generally
Variability
the only
at Colville
being
one of significance.
However,
stations
than norrnal variability,
of the three
with
higher
(Cte EIum
at two are statistically
significant
the values
and PuIIman).
L94As
Western
preciffiificantly
Oreqon.
Most
stations
at
received
corvarris
159
below
and
average
Newport
for
decade on record.
both of which it was the driest
was above
p
r
e
c
i
p
i
t
a
t
i
o
n
Headworks and Ashtand
a
t
A
shland'
r
e
c
o
r
d
decade on
indeed the wettest
Yet at
average,
at all
of Headworks, variability
the exception
with
s
i
g
n
i
f
icant
o
n
l
y
t
h
e
b
u
t
normal
than
wAs less
stations
a
n
d
N
e
w
port.
B
a
n
d
o
n
values are at the two coastal stations,
oregon,
wesLern
tO
contrast
In
Eastern oregon.
the
througtrout
average
above
mostly
preciffi
Hood
and
Baker.
Only
much as it was in the L95As.
iegioir,
below average precipitation.
niver E. S. show slightly
lr/as below
variability
stations
of
majority
the
At
the
of
t
h
r
e
e
At
at
Fremont.
only
signifiiant
normal,
and
a
t
C
o
n
d
o
n
values were above normal, significant
stations
DayviIIe.
Western Washinqton.
srariffiy
and
Centralia
Aberdeen,
decade on record.
driest
at all
Dry conditions
Prevailed
t
h
e
I92As.
i
n
only
exceeded
their
Olympia WSO AP exPerienced
negative
average,
below
generally
was
Variability
other
t
h
e
at
positive
stations,
the
of
at
six
departures
only the low value at Neah Bay is significant.
three.
conditions
average
than
Wetter
Washington.
Eastern
recording
stations
the
of
were ffio-thirds
and Odessa the
At Kennewick
precipitation.
above average
\
rtas the wettest
and it
significant
are statlstically
values
at these two stations.
decade on record
stations,
most
at
above normal
was weII
Variability
the
fact
i
n
t
h
e
s
e
,
o
f
t
t
r
r
e
e
A
t
n
i
n
e
.
t
f
t
e
o
f
out
seven
percent
the
95
at
significant
were
departures
p
- Ioesviet ti v. e
d
e
p
a
rtures
t
h
e
w
e
r
e
a
n
d
Y
a
k
i
m
a
W
a
l
l
a
a
t
W
a
I
I
a
Only
n
e
g
a
t
i
v
e
.
slightly
t9 30s
was below average at all
Precipitation
Western Oregon.
stati@dworkswhichapproximatedttreIong-term
are
statiOns
two coastal
the
at
f.ow values
average.
a
nd
f
o
r
R
o
s
e
b
u
r
g
a
n
d
p
e
r
c
e
n
t
l
e
v
e
I
t
h
e
a
t
9
5
signiiicant
t
h
a
t
n
o
t
e
d
g
g
b
e
s
h
o
u
l
d
p
e
r
c
e
n
t
l
e
v
e
l
.
I
t
t
h
e
a
t
Coivallis
on the north coast tfue decade
at Ast.oria (data not included)
\rtere not as
dry conditiOns
T
h
u
s
a
v
e
r
a
g
e
.
t
h
a
n
$ras wetter
extensive as would appear from the data presented.
above
significantly
was
Headworks
at
variability
but
n
e
g
a
t
i
v
e
,
p
r
e
d
o
m
i
n
a
n
t
l
y
a
r
e
v
a
l
u
e
s
O
t
h
e
r
w
i
s
e
normal.
is not great'
ttre magnitude of the departures
160
w a s w e l l below average
Eastern oregon.
Precipitation
have been
to
conditions
at
affi
dry
showing
prevalent
throughout
the region.
Lovtt values a t f i v e o f t h e
three at the
nine stations
significant,
are statisLicatty
was the
this
level.
At most of the stations
95 percent
driest
decade on record.
below normal throughout
was consistently
Variability
negtive.
However,
departures
being
the
region,
all
values occur only at two of the stations.
significant
Western Washington.
Decadal averges show a range from
below average.
significantly
above average to significantly
stations,
dry
at
a
majority
of
was
relatively
It
was
significant
at Port Angeles.
In contrast precipitation
significantly
above average at Aberdeen and Blaine.
departures
were also
Variability
majority
were positive.
High variability
at Aberdeen and Blaine.
mixed although
a
was significant
the
Washington,
western
Eastern Wastrington.
UnIike
dry.
easte@tate
was everywhere extremely
the
average
at
aII
stations,
was below
Precipitation
departures
being significant
at four of the stations.
Five
driest
decade on
of the nine stations
experienced
their
record.
Variability
where the high
Ievel.
Of the
four of them are
except Conconully
v/as low at aII
stations
value
at
the 95 percent
is
significant
departures,
negative
eight
stations
with
significant
at the 95 percent level.
L926s
Western Oregon.
decade on record
This was the driest
with
regard
to spatial
show below
extent.
stations
AII
average precipitation,
at the 95
four of these significant
percent
it
level.
stations
was the driest
At several
decade on record.
departures
about half
were mixed with
Variability
above normal and half
value at
below.
OnIy the positive
Ashland approaches statistical
significance.
Eastern Oregon.
extent
dry
of extremely
The spatial
condiffiy
the
slighlly
less
than
in
I93Os.
DayviIIe
and Condon show average precipitation
but aII
others
are
at
weII
below
significant
only
average,
Lakeview.
Unlike
not
exhibit
are
about
departures.
the dry decade of the I93As,
the dry I92Os did
particularly
values
low variability.
Station
positive
and negative
evenly
divided
between
l6l
below
welI
was
Precipitation
Western Washington.
except
so at all
significantly
avera@s,
the
for
decade on record
was the driest
It
Centralia.
stations.
region as a whole and for many of the individual
divided
between
were evenly
departures
Variability
t\do
only
values.
Ho\^tever, the
positive
and
negative
at
values are at Neah Bay and Snoqualmie Falls
significant
was less than normal.
which variability
at
was below average
Precipition
Eastern Wastrington.
departure
the
is
at
Spokane
all ffinly
While dryness was extensive it does not aPpear
significant.
to have been as severe as in western Washington.
from
is
the departure
the nine
stations
At none of
for
i
s
a
t
e
n
d
e
n
c
y
T
t
r
e
r
e
s
i
g
n
i
f
i
c
a
n
L
.
v
a
r
i
a
b
i
l
i
t
y
normal
s
t
a
t
i
o
n
s
.
o
f
m
a
j
o
r
i
t
y
a
t
t
h
e
v
a
l
u
e
s
above normal
l-9LAs
precipitation
was near the
In general
Western Oregon.
of
area.
The majority
the
throughout
tong@
do
l
o
c
a
t
i
o
n
a
t
n
o
below average, but
were. slightly
stations
t
h
e
l
o
n
g
t
e
r
m
from
significantly
the decadal values depart
average.
except
stations
all
waS below normal for
Variability
in the extreme southwest part
At the thto stations
Newport.
Ashland and Grants Pass, these low values are
of the state,
at the 95 percent level.
significant
Although not as severe as in the L92As
Eastern Oregon.
the
througtrout
were prevalent
and @onditions
!
'/aS
W
a
l
l
o
w
a
area,
much more sO than in western Oregon.
a
nd
n
e
a
r
a
v
e
r
a
g
e
,
Baker and Burns
above average,
slightly
aII others below average.
variability
of
stations,
At the majorlty
normal, signif icant at three of six stations.
was above normal.
three statj-ons variability
was
At the
beLow
otrrLer
received
of stations
The majority
western wlshington.
precipitation,
none of the values
slig@e
dt Neah Bay it was
In contrast,
significant.
statistically
the driest decade on record.
were
variabitity
normal
from
departures
Negative
vafiability.
show high
two
stations
dominant.
Only
the high value is significant.
However, dt Centralia
Eastern
With regard to annual precipitation
the
from
Departures
unremarkable.
above
those
between
evenly
divlded
Wastrington.
decade
\^ras qilte
the
mean are
Iong-term
16?
average
and
significant.
those
below.
None
of
the
departures
are
are dominantly
negative,
only
departures
Variability
Colville
among the nine stations
experiencing
above normal
variability.
stations
are the
However, dt none of the
values significant.
19AAs
Western Oregon.
from average precipitation
Departures
wereffint
throughout
the area,
being
divided
between
those
above
and
those
below
their
long-term
average.
are significant
at the 9g percent
Two values
Ievel,
Grants Pass above average in the souttr and Headworks
below average in the north.
the most stable decade on record with
It was certainly
all
stations
experiencing
very
low
variability.
The
departures
at seven of the nine stations
are statistically
significant,
four of them at the 95 percent level.
Eastern
out@
Or_egon.
Wet conditions
Five
of
the
were dominant throughseven
show
stations
precipitation
Lakeview.
average.
well
above average,
significant
and
Prineville
WaIlowa
were
at Burns and
slightly
below
departures
Variability
were mixed,
four
of seven
negative.
values
at
Low
Baker
and
Prineville
significant
at the 95 percent
level.
being
are
Western Washington.
decade
was similar
to
the
This
jority
191oma
of
received
above
stations
precipitation,
average
the
values
significant
at
Olympia
WSO AP and Tacoma.
Two stations,
Neah Bay and Snoqualmie
Falls
were slightly
below average.
the
With
exception
experienced
below
normal
and Olympia,
Blaine
these
level.
95 percent
of
all
Balr
stations
Neah
variability.
two
stations,
At
low values
are significant
at the
Eastern
Washington.
The majority
of stations
received
srig6@ab-6Fe
precipitition-but
average
in no case was it
siEnificantly
dj-fferent
Lhan the long-term
average.
Those
few stations
drier
than normal were also only slightly
so.
The
majority
of
stations
experienced
normal
below
variability,
significant
at
three
of
stations.
two
At
these,
Conconully
and Odessa the negative
are
departures
pullman
significant
at
the
level.
was above
95 percent
normal
and at
to
the
Walla
Walla
variability
was equal
long-term
value.
.|63
l89Os
precipitation
on.
At Eugene and Portland
in
below
contrast
to
the
other
average,
stations
which were all above average.
dt Roseburg
In fact,
and Bandon it was the wettest
decade on record ( 1880-1979) ,
Departures from normal variability
were mixed.
At five
of the eight stations,
departures were negative,
significant
at
positive
Eugene.
three
values,
that
at
Of the
only
Bandon is significant.
the
five
stations
with
data
Eastern Oregon.
Of
avaiffiweI1aboveaverageprecipitationforthe
decade.
Ert Baker and Hood River E. S.
Two of these values,
are significant
at the 95' percent
level
and it vras wettest
decade on record.
Burns was a sharp contrast
to these with
precipitation
significantty
below average.
positive
departures
at
three
Variability
were mixed,
stations
and negative
at two.
the
The only value reaching
is the negative value at
95 percent leve1 of significance
DayviIle.
Western Washington.
The decade was quite
with
wet
deca@ally
well
above average.
The values
at
Blaine,
and
Neah Bay,
Port
Angeles
Tacoma were
significantly
wetter than average.
was it
OnIy at Centralia
slight.ly
drier than average.
at
was generally
1ow, negative
departures
Variability
seven of the nine stations.
Only at Aberdeen is the value
significant
even at the 9A percent
level.
and
At Blaine
was slightly
above normal.
Olga variability
at
Eastern Washington.
Kennewick
Precipitation
srig@
but at the other three stations
above
significantly
average.
averages
was
Decadal
Pullman and WaIIa Walla were the greatest
on record.
None of
significance;
the departures
from normal variability
two were positive
and Lwo negative.
were
was
it
at
of
188Os
Western Oregon.
deca@on
significant
Portland
four
stations
with
At all
was above
average
with
at the 9O percent
level.
data for this
the
value
at
Bandon
and
both
experienced
slightly
below
Roseburg
variability
normal
whl-Ie
and
the
at
Ashland
Portland
departures
were positive
and significant
at the 9g percent
1eve1.
164
Eastern Oregon.
years
five
OnIy
record
of
are
avaiffiiew
and Hood River E. s.
Thus, for the
year 1885-f889 Hood River E. S. was slightly
wetter
than
average and Lakeview slightly
drier
ttran average.
Variabirity
was srightly
higher
ttran normar
River and significantly
below normal at Lakeview.
western washington.
The decade was quite
nngeffiy
above
average
at
Precipitation
at Tacoma bras near its long-term
Olympia slightly
below average.
at
Hood
wet at port
Neah
Bay.
mean and at
variabirity
departures
were arso mixed and none of the
values
are
significant.
At
orympia
variability
was
srightly
above normar
and at
the bther
three
stltions
values were slightly
below normal.
Eastern washington.
At the only two stations
for which
data@kane
and wafia wallar
precipitation
was significantly
above average.
variability
although neittrer
at
both
departure
stations
vras
is significant.
rower
than
normal
I87As
oregon.
only data from portrand
is available
and it
shows an extremery
wet decade,
in
fact
the wettest
on
record.
j_n
Reference to the time series
plot
of Astoria
Appendix E wilr
show that at that rong-term
station
it was
also the wettest
decade on record ( fgSa-fg7g) .
The decadal
varue of variability
at portrand was srightly
above normal.
Washington.
Data
is
available
only
at
WaIIa
Walla
and
it
irljIEaEes
conditions
approximately
equal
to
the
Iong-term
mean.
Variability
at
WaIIa
WaIIa
was
excep'tionarly
high,
significant
at the 95 percent
lever.
However, the sample here is only six years.
Summary
The one obvious
concrusion
that
can be made about
changes in pacific
Northwest precipitation
over the past
lgg years
is
that
one shourd not generalize
trends
and
fructuations
in a region where spatial
variability
is so
great.
The analysis
of rong-term trends aL 76 stations
in the
Pacific
Northwest indicales
ttrat there has been no uniform
increase
or decrease
in
annual precipitation
throughout
Oregon.
In
Washington
there
tras been a tendency
for
declining
totars
over the last Lga years.
However, only a
165
few of
very
statisticatly
statistics
the trend
signif icant .
are
of
a
magnitude
to
be
of
spite
in
shows that
series
time
filtered
of
study
in
t
r
e
n
d
s
t
e
r
m
y
e
a
r
,
s
h
o
r
t
y
e
a
r
t
o
from
rapid
osclllations
p
a
r
t
l
a
t
t
e
r
t
h
e
f
r
o
m
t
r
e
n
d
d
o
w
n
w
a
r
d
A
do exist.
the series
f
e
a
t
u
r
e
a
i
s
a
b
o
u
t
L
9
3
g
u
n
t
i
l
nineteenttr
century
of
the
Northwest
the
throughout
Pacific
noted
at
most
stations
t
h
e
L
9
3
A
s to the
F
r
o
m
e
x
c
e
p
t
i
o
n
s
.
a
r
e
s
o
m
e
although
there
O
r
e
g
on is a
i
n
w
e
s
t
e
r
n
f
o
r
s
t
a
t
i
o
n
s
L97As an upward trend
y
e
a
rs have
t
h
e
l
a
s
t
4
A
a
r
e
a
s
i
n
o
t
h
e
r
feature.
Yet
dominant
v
a
l
u
e
.
S
e
quences
m
e
a
n
c
o
n
s
t
a
n
t
f
a
i
r
l
y
a
around
fluctuated
b
e
e
n few,
h
a
v
e
r
e
g
i
o
n
s
t
h
e
w
e
s
t
e
r
n
y
e
a
r
s
i
n
of wet and dry
E
ast of
i
s
o
l
a
t
i
o
n
.
i
n
t
o
o
c
c
u
r
y
e
a
r
s
t
e
n
d
i
n
g
extreme
with
p
r
o
l
o
ngqd
m
o
r
e
b
e
e
n
h
a
v
e
d
r
y
c
o
n
d
i
t
i
o
n
s
the Cascades wet and
from
a
n
d
m
a
g
n
i
t
u
d
e
i
n
d
u
r
a
t
i
o
n
considerably
and have varied
to another.
one place
also
means and variability
decadal
of
comparison
a
n
n
ual
m
e
a
n
i
n
fluctuations
that
it
clear
makes
not
h
a
v
e
t
n
e
a
n
t
h
e
about
precipitation
and in the variability
to
Northwest
the
Pacific
of
from one part
been consistent
d
e
c
a
d
a
l
consistent
the only
that
another.
The data indicate
t
h
e
L
9
7
f
r
s
,
of
variability
high
are the extremely
anomalies
d
e
c
a
d
e
s
d
r
y
t
h
e
the wet decades of the 1890s and I95As and
for
tendency
There is no apparent
of the L92As and 1930s.
u
n
i
s
on
i
n
either
mean to vary
from ttre long-term
departures
variability.
from long-term
to departures
or in opposition
A
two
consider
to
interest
is
of
it
conclusion,
In
w
et
unusually
the
years,
specifically
extreme
selected
(
f
i
g
u
r
e
of L977
dry winter
unusually
of 1956 and the
winter
extreme
the
that
suggest
would
comparison
This
23).
more
b
e
t
o
tend
years
seasons
or
dry
of
conditions
y
e
a
r
s
.
In
w
e
t
of
conditions
the
extreme
ttran
widespread
t
h
a
n
L
4
g
m
o
r
e
received
region
the
much of
winter
1956
i
t
s
t
a
t
i
o
n
s
and at several
precipitation
percent
of normal
yet
the 4A year normal periodt
during
winter
was the wettest
n
o
r
m
a
l.
t
t
r
a
n
wetter
slightly
it
was only
at many stdtions
t
h
e
t
h
r
o
u
g
h
o
u
t
dry
winter
L977 was uniformly
In contrast,
d
r
i
e
s
t
t
h
e
it
was
exception
without
Almost
Northwest.
received
Muctr of Lhe region
of the 46 year period.
winter
This
p
r
e
c
i
p
i
t
a
t
i
o
n
.
winter
of
normal
below
4b percent
wet
a
b
n
o
r
r
n
a
l
l
y
for
other
true
holds
generally
relationship
and dry years.
166
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B d a
Osf
oo\
. d F {
(no
c{(n
o >o
LO
Lf)
Or
! t{'r{
'A+J
td
Ut.r{
+J
h f*'.{
L
(u
r-q
+t
O\ .Fl
F { O
=
(o
167
Vf.
CONCLUSIONSAND SUGGESTIONSFOR FURTHERRESEARCH
rt
i-s criticar
to
rearize
that
variabirity
is
an
inherent
characteristic
of erimate,
a characteristic
the
worrd has become much more familiar
with in recent years.
rn the Pacific
Northwest the variabirity
of precipitation
ig unusuarly great, both spatiarry
and over a wiae range of
time
scales.
These variations
must be given
careful
consideration
in all aspects of water resource pranning.
In
this
study
monthlyr
s€dsonal
and
annual
precipi-tation
characteristics
were examined for
a dense
network
of
ctimatorogical
244
stations
in
oregon,
washington
and adjacent
areas.
The prirnary
data
base
deveroped
for
anarysis
incrudes
monthty
f
r
e
c
i
p
i
t
a
t
i
o
n
totars
for the 46-year base peri-od Lg4g-rg7g.
The monthly
data were further
combined into
(october
winter
ttrrough
Aprir),
sunrmer (uay through
september) .rra
(water
year) totals.
"""""r
various statistics,
descriptive
and inferentiar,
were
calcurated
to
define
aspects
of
variabirity.
rrr.
key
statistics
are the mean and the variabitity
ab6ut the mean,
expressed by the coeffi-cient
of variation.
Three different
formats were used to summarize this mass of data:
a set of
isopleth
maps depicting
means and coefficients
of variation
for individuar
months, seasons and the water year; annuar
profires
of monthly means and coefficients
of variation
at
43 stations;
and a set of isocorr
maps showing interstation
correlations
on a monthly and se.sonal basis.
patterns
of precipitation
were shown to be
_ The spatial
a function
of the interrerated
influences
of three dominant
climatic
contrors
ratitude,
topography and continental
versus
marine
influence.
The general
form
of
these
patterns
is predictable.
However, rerative
variability
is
particularly
complex.
Highest
values
appear
to
be
immediately
to the ree of th; cascades; yet the far eastern
portions
of
oregon
and washington
rerativerlr
- s e a s o ir.n"
nal
row
variabirity.
variations
in the
concentration
of
precipitation
do not completely
expl-ain this contrast.
The anarysis
of spatiar
aspects of precipitation
and
its
associ-ated variabiiity
tended to raiJe *oi"
l
u
e
s
t
i
o
n
s
than
it
answeredr
of
significance
![ueslions
to
both
crimatologists
and to water
resource
managers.
several
aspects require additional
research, for example:
169
to
be
it'y
need
variabil
patterns
of
Monthly
I )
for
Valley,
in more detail.
In the Willamette
considered
is
example, while December is the wettest month, variability
type
of this
least
in I'larctr.
Many observed relationships
to explain.
are difficult
need to
2) Apparent anomalies in means and variability
circulation
be examined in terms of features of the general
features.
in controlling
and the seasonal shifts
The
3)
precipitation
detail.
of
influence
and variability
on mean
the
Columbia
Gorge
needs to be studied in greater
statistical
great
variety
of
The
4)
in
e
v
a
luated
variability
must be compared and
usefulness to water managers.
of
indices
terms of their
of
problem
that
is
interesting
A particularly
5)
t
h
i
s
o
f
r
e
g
i
o
n
s
.
C
o
m
p
l
e
t
i
o
n
tromogeneous climatic
defining
a
u
s
i
n
g
o
u
t
b
e
c
a
r
r
i
e
d
analysis to
task wiII permit climatic
network of stations.
smaller, but representative,
6) Similar
data
temperature
and precipitation,
analyses need to be done on
statistical
temperature
elements,
and the two climatic
with snowpack data.
should be correlaLed
section of this report deals with changes in
The final
years,
the
Iast
precipitation
the
L66
over
annual
l
o
n
g
t
e
r
m
period.
for
7A
Data
secular
instrumental
or
g
r
a
p
h
s.
stations
were compiled and presented in time-series
w
e
re
data
series
these
analyzing
of
techniques
Three
T
r
e
n
d
information.
yielded
important
and alI
employed
a
n
n
u
a
l
o
f
amounts
analysis
showed a tendency for decreasing
e
i
t
h
e
r
f
o
r
no tendency
precipitation
but
in
Washington
time
Fitt.ered
amounts in Oregon.
increasing
or decreasing
of
trends
short-term
a
number
of
series
emphasize
f
o
u
n
d
.
was
uniformity
spatial
significance.
However, little
t
o
from the 1890s
Onty the gradual decrease in precipitation
Otherwise,
about L93g is a standard feature for the region.
from one
fluctuations
in precipitation
there are contrasts
area to another.
For example, in western Oregon an upward
trend
from the 1930s to the L976s is a domi-nant feature.
values over the
Northwest
of the Pacific
Yet in the rest
about a relatively
last
4A years have tended to fluctuate
constanl mean.
were calculated
Decadal values of means and variability
in Oregon and Washington.
for 36 of the lo:ng-term stations
changes
that
the finding
reinforced
This form of analysis
from one part of the region to
over time are quite different
another.
Certain wet decades, the 1890s and 1950s, stand
But the most
out as do dry decades , I92As and the 1939s.
the
is
analysis
the
decadal
of
feature
consistent
r70
interannual
variability
of
annuar precipitation
in
the
r97os.
Extremely
high
variability
is
obvious
at
alr
stations.
This finding
is consistenl
wittr studies
from arr
parts
of the grobe and may support
the contention
of some
scientists
that we have enlerea a period of grobar crimate
distinguished
by its
extreme vafiabitity
prace
fro*
to
place and from year to year.
Many suggestions
can also
be
analysis of long-term data series:
1) The severity
and spatial
needs to be described on a finer
made
extent
scale.
of
for
subsequent
drought
periods
2) Fluctuations
i n m e a n s a n d v a r i a b i l i t y - A mneerei cda nt o b e
specifically
compared with other parts of the
west
and correlated
with
changes in
indices
of
the
generar
circulation
of the atmosphere.
3) The spatial
annual
precipitation
homogeneous climatic
extent
of trends
and fluctuations
need to
be defined
in
terms
regions.
in
of
4) Year-to-year
and season-to-season
persistence
needs to be studied to determine if there
^Drecipitation
any value for forecasting.
in
is
The findings
of this
study and the data presented
shourd be of use to two categories
(ri
of users:
persons
and agencies invorved in land and. water resource management
whose effectiveness
wourd be improved by the direct
and
immediate apptication
of detaired
knowledge on the natural
variabirity
of lDrecipitation;
and (z) persons i_nterested in
the
broader
topic
of
crimatic
change.
climatic
fluctuations,
of any magnitude and duration,
have become
increasingry
rerevant
as
we
approach
the
maximum
utirization
of rimited
water resources.
simirarry,
at a
time
when
man's
potential
for
inadvertent
climate
modification
is
a rearity,
it
is
necessary
to
make
avairable
a comprehensive
anarysis
of
naturJr
crimatic
variabirity
in order to monitor and document the effects
of
man's use of the environment.
et al
rn concrusion
it is
(fgZer p. L79)z
appropriate
to
quote
from
pittock
....the
effect
_of bhe topography is to amplify
quite
smarl exchanges in lrte g-enlrar- circut-atioi
so that much rarger
magnitude effects
are often
observed
in particurar
locations.
This appr ie's
particularty
to
precipitation
in
mountainous
areas,
and thus to watersheds and runoff.
The
differential
nature
of
the
water
bal_ance
relationships
adds
to
the
171
critical
nature
of
these effects.
is
therefore
It
not surprising
that
the most dramatic
flucLuations
in observed
climatic
variables
are
those
affecting
water
supply and river
flow.
The social
and economic
consequences of these fluctuations
loom larger
as
populations
grow and existing
water resources are
increasingly
utilized.
172
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Spatial variation
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1948.
Pacific
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Western Construction
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1966.
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Weather and climate
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1956. Variabitity
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196I.
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o
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o
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Journal of
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On the response of hemispheric mean
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An empirical
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o
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r
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e
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e
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Long-range requirements
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1956.
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Washington state.
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al
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Climatic
change and
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A southern perspective.
Cambridge University
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London:
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ation
Ca
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Los Angeles:
ornia
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University
c. B.
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1966.
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1966.
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of historical
Oregon and Washington,
I82L-L964.
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M. J.
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I.
PrecipiNew Zealand climate:
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between topography
Relations
1967.
Schermerhorn,
V. P.
a
n
d
Washi-ngton.
in western
Oregon
annual precipitation
Water Resources Research 327A7-7LL.
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Root growth-rings
Schulman,
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Tree-Ring Bulletin
.
Runoff histories
1947.
Geographical
Pacific
Slope.
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1956.
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and chronology.
semi
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Universlty-ffi
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trends
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28th Western Snow
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Proceedings
Santa F€, New Mexico.
Conference:
8I-94.
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1968.
patterns
in
of monthly
Climatology
vrestern United
States.
precipitation
Monthfy We.ethe!
Review 96:585-595.
-tTons
A reassessment of the effect
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model .
climatic
on a simple global
Applied Meteorology
13 :831-833.
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Sharon, D.
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Correlation
1979.
field.
Monthly
o f C O , . ,v a r i a of
Journfl
analysis
of the Jordan VaIIey
Weather Review LA7zLA42-L947.
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M. L.
1977.
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Weatherwj-se 3AzI39-I53.
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Extent
RecenL activiE. L.
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1931Drought in the United States,
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L949.
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Correlations
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wireatgrass
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3 A z 2 7 A - 2 75 .
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.|80
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1967.
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62255-264.
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1965.
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I95O. Ternperature
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.
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Recent statistical
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Australia
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r8l
su.oport of
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southwestern
I',lonthly
APPEHDIGE$
YAftIfiSILITYSF PRESTPITATI6N
Ift THEFAETFNC
}ff}Hf,'f.*JEST:
SPATIALAI{DTEilFORAL
CHARAETERI5TICS
by
D a n i e l M . J o h n s o na n d J o h n0 . D a r t
D e p a rtme not f Geogr aphy,
Por tland State Univer sity
A P P E N DA
IX: N ETW ORK
OF CLIMATOLOGICAL
STATIONS
A- l to A- l 0
A P P E N DBI X
: D E S C R I P T ISVTEA T I S T I C( .S| 9 4 0 - . | 9 7 9 )
( F o r M o n t h l y ,S e a s o n aal n d A n n u a lP r e c i p i t a t i o n )
B- l to B- 42
A P P E NDIX
C: SKEW NESS
STATISTIC
( F o r M o n t h l y ,S e a s o n aa' ln d A n n u a lP r e c i p i t a t i o n )
c - 1to
C - l0
A P P E N DD
IX: C ON FIDENCE
INTERVAL
PRECIPITATION
OFMEAN
(95%, 99%)
D-1 to D - 6
AP P E N DE
IX: P R E C IP ITATION
DATASERIES
FORLONG- TERM
STATIONS
(AnnuaT
l o t a l s a n d M o v i n gM e a n )
E - l to E- 78
WATER
RESOURCES
RESEARCH
INSTiTUTE
0 regonState Univer sity
Corvallis,0regon
Append
i ces
- 77
t,lRRI
APPENDIX A
NETWORK OF CLIMA'fOT,OGICA,r, .S,TATtrONS
A-l
DATA NETI{ORK:
WATER YEARS I94S-I979
( oREGON)
Stat ion
E
st97
9265
s394
g3t8
9328
s356
g4t2
g 417
647r
s 6 94
s 72 3
0897
1S55
r I76
L2S7
1433
I s46
r552
r571
1643
r765
r862
1897
t9g2
r926
1946
2LT2
2135
2r68
2277
2456
2440
2633
267 2
2593
2 7g 9
28s5
2997
3s95
3121
3355
3452
3445
3542
Name
(1)
(2)
(3)
(4)
(s)
{6)
t t t
Latitude
Ante lope
Arl ington
Ashland
Ascor Experiment Station
A s t , o r i a U | S OA P
Austin 3 S
BaKeT FAA AP
Baker KBKR
Bandon 2 NNE
Bend
Beulah
Bonneville Dam
Brook ings
B u r n s W S OC I
Butte Falls 1 SE
Cascadia
C h e m u It
Cherry Grove 25
Chiloquin I E
Clatskanie 3W
Condon
Corvall is-Stare Univ.
Cottage Grove I S
Cottage Grove Dam
Cove
Crater Lake NPS HQ
Dallas
Danner
Dayville
Detroit
Drain
Dufur
Elkton 3 SW
Enterpr i se
Estacada 2 SE
Eugene WSOAP
Falls Ciry 2
Forest Grove
Fremont
Fr iend
Gold Beach Ranger Station
Government Camp
Grants Pass
Gr izzly
A-3
44
45
42
46
46
44
44
44
43
44
43
45
42
43
42
44
43
45
42
45
45
44
43
43
45
42
44
42
44
44
43
45
43
45
45
44
44
45
43
45
42
45
42
44
55
43
L3
09
S9
3s
5S
46
09
S4
55
38
S3
3s
32
24
14
25
35
06
14
39
4'7
43
18
54
56
56
28
42
4g
27
36
26
16
s7
51
32
20
2t
24
18
26
31
Longitude
Elevarion
r2s 43
T2S 12
L22 43
I23 49
I23 49
1t8 30
LT7 49
117 5s
t24 24
121 19
118 1S
r2r 5'l
L24 t7
rl9 s3
L22 33
r22 29
t2t 47
123 1s
121 51
T23 I7
I2O IT
T23 12
r23 04
I23 s3
I17 48
t22 g8
123 19
TI7 20
119 32
r22 07
r23 l9
Izt s8
123 35
117 l6
t22 L9
123 13
t23 26
r23 S6
IzL Ig
]2I I6
I24 25
121 4s
123 19
r20 56
2695
285
I78S
48
8
42I3
3368
3444
2S
3655
327 g
60
g0
4r4S
2500
86s
4 76 0
780
4220
92
2830
zz>
65s
831
2920
6 4 75
325
4225
2354
L452
292
L33S
r2s
319s
4rs
364
440
r8s
4512
2 44 0
50
398s
925
3635
(oREGON)
Station
E-
Name
3604
3692
3 1 7S
3827
384't
39s8
4gs3
4098
4133
4 1 6r
4291
4403
44r1
45A6
4622
46'70
{81I
5S8s
5 l 5S
(8)
(9)
(10)
5r62
5362
5384
5424
).t zt
5 5 93
5 73 4
6932
6 g ' 73
5 1 79
62r3
6243
64s5
6 426
6458
65 4 6
6634
6'749
6825
5883
6997
(11)
(12)
H a 1f w a Y
Hart Mountain Refuge
Headworks, Portland
water Bureau
HePPner
2 s
Hermiston
Hillsboro
Hood River ExPerlnent
station
Huntington
Illahe
Ione 18 S
John DaY
Keno
Kent
Klamath Falls 2 SSw
LaGrande
Lakeview 2 NNW
Leaburg l Sl'l
Lovrer HaY Creek
Madras
Malheur Branch
ExPeriment Scat ion
Malheur Refuge HDQ
trlcXenzie Bridge Ranger
Stat ion
Mcf4innvilIe
M e d f o r d E x P e ri m e n t
Station
F t e d fo r d v . l s o A P
Milton Freewater
lilo r o
N e w P or t
North Bend FAA AP
Nyssa
Oakridge Fish HatcherY
Ochoco Ranger Station
Owyhee Dam
PaisIeY
Parkdale 2 sSE
Pendleton WSOAP
Pilot Rock I SE
Portland KGw-Tv
Povrers
Prineville
ProsPecE 2 Sw
A-4
Latitude
Longitude
Elevation
44 53
42 33
45 27
tL7 g'l
1r9 39
L22 09
2 6 7g
5616
748
33
17
59
3T
r95s
d5
45
45
45
2r
49
3I
41
r19
119
r22
I2I
44
42
45
44
42
45
42
45
42
44
44
44
43
2r
38
19
26
07
L2
12
19
13
65
44
38
59
117 r6
I2A 93
]19 5I
118 57
T2T 57
L2g 42
T2I 47
118 06
r20 22
L22 4T
t2s 59
L2T 08
IT7 OT
2I3g
348
2t3S
3563
4 1 r5
2'l2g
4698
2755
4778
675
1898
2230
2249
43 r7
44 11
118 50
r22 S7
4rs9
r4'l I
45 14
42 18
I23 I1
t22 52
r48
L45'7
52
25
43
S3
15
Sg
27
26
15
32
35
s1
49
4T
g4
54
3r
1312
975
r81S
154
42
45
45
44
43
43
43
44
43
42
45
45
45
45
42
44
42
22
5'l
29
38
25
52
4s
24
39
42
3S
4l
29
3l
53
2r
44
L22
r18
t20
r24
124
TT7
r22
L20
117
Izs
I21
lr8
1r8
L22
t24
r2a
t22
624
r60
504
2L7 5
L27 5
3975
2400
a36s
194s
t492
t72S
159
230
2845
2482
(oREGON)
Stat ion
T.D;7s 5 2
7982
7 169
7208
7 259
7331
7354
7599
764I
8s29
8407
I 456
8494
6 t z b
8 74 6
8 78 g
8 79 7
8818
8833
8884
8997
9s68
93 1 5
Name
L at i t u d e
Redmond 2 W
Reedspo r t
Ridd I e
(13) Riverside
Rock Creek
( 1 4 ) Roseburg KQEN
Round Grove
Sal.em WSO AP
Seaside
Squaw Burte Experiment
Station
(rs) The Dalles
Three Lynx
Tillamook I W
Ukiah
Union Experiment Station
Unity
vale
(16) Valley Falls 3 SSE
Valsetz
( 1 2 1Vernonia 2
W a l .l o w a
Wasco
Wickiup Dam
Long i tude
44
43
42
43
44
43
42
44
45
a3
16
42
57
33
55
t2
2g
55
59
29
123 55
r19 41
45
45
45
45
45
44
43
42
44
45
45
45
43
36
g7
27
g8
t3
26
s9
27
51
52
34
3s
41
T2T 12
L22 g4
r23 52
118 56
117 s3
118 14
l1? 15
I2g T5
r23 4S
123 t1
It7 32
r2g 42
T2I 4I
58
31
58
t2
47
47
o0
sg
34
TO
25
43
5g
723
r22
r22
I22
r22
I22
r2s
I22
r22
L22
T2T
t22
49
37
34
08
32
29
t8
45
4s
00
44
57
r2s s2
I7
57
58
tI
IT9
I17
r22
122
I2g
S4
43
47
20
57
12r
t24
I23
118
118
123
t3
07
2I
19
04
2L
rzs 53
t23 gr
Elevation
3Sr0
5g
680
333s
4933
465
4 8 88
195
TS
4 6 55
r62
IT2S
IO
J5)l
2 76 5
4g3L
224A
458s
1 1 55
625
2923
r264
43s8
(tiASHINGTON)
9008
0 1 76
s242
0257
0482
9 5 64
0658
s 72 9
9 8 12
0 94 5
r233
I21 6
1350
1414
I484
r504
Aberdeen
Anacortes
(18) Ariel Dam
Arlington
Battle Ground
Bell ingham 2
Bickleton
Blaine
Bremer ton
Buckley I NE
Cedar Lake
Central i a
( l9) Chelan
(29) Chesaw 4 NNw
C h e w e1 a h
Chimacum 4 S
Clearbrook
Cle Elum
46
48
45
48
45
48
45
49
47
47
47
46
41
49
48
47
48
47
A-5
s0
Lg
3s
224
I60
295
r4s
3ggg
60
L62
58s
r560
I85
tI2g
3960
r6"l s
IAg
64
1930
(vJASHTNGTON)
Station
-T5;-
I 586
L650
t665
L679
t760
I767
I 7 83
1934
I 968
1992
Name
(21)
2ss7
2g3S
2157
25s5
2531
2 6 75
2 9r 4
3222
328 4
3357
3502
3529
3546
39?s
4977
4 0 84
4r 5 4
4 2 5r
4338
4 3 94
44A6
4414
4446
4486
4549
4 5 72
4 6 79
4 76 9
4 9 7r
5r28
5224
5425
5525
56r3
5 65 9
5688
5794
(22)
(23)
(24)
(25)
(26)
(2?)
(28)
Colfax I NW
Colville
AP
Conconully
Concr e te
Cougar 6 E
Coulee Dam I SW
Coupeville 1 S
Cushman Dam
Dallesport
FAA AP
Darrlngton Ranger SEaEion
Davenpo r t
Dayton I WSI{
Diablo Dam
El I ensbu rg
Elna
Everett
Forks 1 E
Goldendale
Grapeview 3 SW
Gr e e n w at e r
Harrington 5 S
llartl ine
llatEon 9 ESE
Irene Mt. Wauconda
Kahfotus 5 SSW
KaIama Falls Hatchery
Kennewick
Kid Va1ley
La Crosse
Lake Cle Elum
Lake Kachess
Lake Keechelus
Lake Wenatchee
Landsburg
Laurier
Leavenworth 3 S
Lind 3 NE
L o n gv i e w
Mansfield
Mazama5 SE
McMillin Reservoir
Mineral
llon roe
Moses Lake 3 E
Ht. Adams Ranger Station
Moxee City 16 E
Irlud l,lountain Dan
A-6
Lacltude
Longitude
Elerration
46 53
48 33
48 33
48 33
46 s4
4'7 57
48 12
47 25
45 37
48 1s
47 39
46 19
48 43
46 58
47 Sg
47 59
47 57
45 49
47 I8
47 g8
47 25
47 4t
46 45
48 49
46 3s
46 0t
46 13
46 22
46 49
47 15
47 16
47 L9
47 5S
47 23
49 gS
47 34
47 g0
46 s9
47 49
48 32
47 S8
46 43
47 5t
47 S7
45 00
46 3r
a7 g9
It? 23
ll7 s3
rl9 45
IzL 46
T22 L2
TI9 Sg
r22 42
r23 13
T2T S9
121 36
118 S9
TI8 OO
t2L 09
r2s 33
r23 24
T22 TL
L24 22
I2S 50
L22 52
r21 38
118 1s
II9 g6
118 39
1r8 54
TI8 36
122 43
ILg S6
L22 37
1I7 53
LzL 94
T2T 12
T2I 2S
I20 48
121 58
1r8 14
I20 4S
118 35
I22 55
1r9 38
I20 20
I22 16
L22 LI
121 s9
119 12
T2T 32
L 2 OL O
121 56
1955
1885
2329
19s
6s9
I7g0
5s
765
222
559
2469
I 557
891
t48S
7S
6s
355
r6ss
30
I73g
2I7 g
r910
r430
27gg
I 550
3r0
39s
699
I480
2255
2 2 70
2 4 75
2sg5
535
1644
r 128
r63g
T2
2265
1966
579
1 4 70
L2S
L2S8
195s
1550
1308
(t{ASHINGTON)
Stat i on
E_
58gI
5832
5840
5844
5946
6439
6095
6114
6L23
6295
65s3
66L0
6624
6 6 7I
6768
6 78 9
5893
6845
6880
6895
59s9
6 9 ' t4
7938
7959
7r 8 g
7473
7478
15A'r
7538
7584
7 7 73
7938
79s6
7987
8934
89 s9
8207
8286
8348
8773
8931
8959
9gr2
9058
90'14
9238
9 321
9342
9 3 76
9 45s
Lat i tude
Name
Neah Bay 1 E
Nespelem 2 S
(29) Newhalem
Newpor t
Nor thPo r t
Odessa
Olga 2 SE
Olympia wso AP
Omak 2 NW
PaImer 3 ESE
Pfeasant view
Pomeroy
PorE Angeles
Port Townsend
Prosser 4 NE
Pullman 2 NW
Puyallup 2 w ExPeriment
Station
Quilcene 2 SW
Quincy I S
Rainier Ohanapecosh
Randle I E
R ep u b l i c
Rimrock (Tieton Dam)
Ritzville
I SSE
Rosalia
(39) Seattle-Tacoma wSO AP
of Wash.
Seattle-Univ.
Sedro WooIey
S e g ui m
Shel ton
Snoqualmie FalIs
Spokane wSO AP
Spr ague
Spr uce
Startup I E
Stehekin 4 NW
Sunnys i de
Tacoma City Hal1
Tekoa
Vancouver 4 NNE
walla walla wSO Cl
v{apa Eo
Waterville
Wellpinit
W e n at c h e e
WiI bur
Wilson Creek
(31) Wind River
winthrop
1 wslt,
Y a k i m a W S OA P
A-7
Longitude
48
48
48
48
48
47
48
46
48
47
46
46
48
A8
46
46
47
22
08
4I
l1
55
2g
37
58
26
18
31
28
97
g7
15
46
12
r24
118
121
LL7
1l?
118
L22
t22
119
121
118
1r7
L23
L22
rl9
IL7
r22
3'l
59
15
S3
47
41
48
54
32
5l
20
37
26
45
4s
T2
2S
47
a7
46
46
48
46
47
47
47
47
48
48
47
47
47
47
47
a7
4A
46
47
47
45
46
46
47
47
47
47
47
45
48
46
49
t3
44
32
39
39
g'7
tA
27
39
39
05
12
33
38
t8
48
52
2t
19
13
13
41
02
26
39
53
25
45
25
48
28
34
r22
119
I2L
12r
118
55
51
34
56
44
t2r s8
Ltg 22
tr7 22
TZ2 L8
I22 T7
L22 14
I23 96
r23 06
121 5l
IL7 32
11? 59
r24 S4
121 43
L2s 43
I2S OS
L22 26
II7 g5
L22 39
tr8 2s
r2s 25
r2s s4
117
T2g
118
IT9
121
I2g
59
L9
42
g7
56
ll
r2s 32
Elevation
tg
1899
525
2 13 5
1 35 9
L54g
8g
192
L228
929
r 6 65
t810
Lgg
r0g
9s3
2545
5s
r23
t z
t q
195S
900
26ls
2 13 0
1830
24gs
459
95
6g
180
22
44s
2349
192g
36s
11g
r27 g
7 4'7
257
26L0
2Lg
949
855
262s
2430
634
2r6S
r27 6
It45
1755
tg64
( rDAHO)
SEat i on
-=ii-
Name
1 3 80
l9 56
3 7 7r
6L52
6 424
6844
689I
't
254
7386
7796
8s62
Latitude
Longitude
Efevation
43 40
47 4r
45 55
46 44
46 15
43 48
44 s5
49 g0
48 21
45 25
4'7 19
1r6 41
1I6 45
II6
116
116
115
II5
rl6
1I6
rr6
116
O8
s8
15
57
56
39
50
18
34
237 0
2 15 8
3360
2660
3 1 45
22r5
3 1 45
L 7 75
2380
7800
2229
40
4I
41
46
5g
57
3g
54
115
1I6
1I7
117
47
05
32
48
5 0 75
5396
4 5 75
4291
32
46
5]
48
58
43
Lzg 16
T24 L2
467g
40
4509
I2IO
4s35
2625
Caldwell
Coeur DrAlene Ranger Station
Grangeville
Moscolr-Univ. of Idaho
Nezperce
Parma Experiment Station
Payette
Porthill
Priest River ExPer. Sta.
Riggins
s a i n t M a ri e s
( NEVADA)
z >t5
5869
6905
> L I L
Elko FAA AP
Ohryhee
I Nv,l
Paradise valIey
W i n n e m u c c a W S OA P
( C A L IF O R INA )
1614
2r41
3I57
3761
9s53
9866
41
41
4l
41
41
41
Cedarville
Crescent City IN
For E Bidwel I
Happy Camp Ranger Station
Tulelake
Yreka
r2s s8
r23 22
I2L 28
L22 38
F o ot n o t e s
(l)
Station
closed July
(2) Station opened February I953,
station).
(3) Starion
Grove.
to date
19?3, data
opened January
data
6382: Astoria
is
data
Prior
1944, prior
is
wSOAP.
(compatible
0324: Astoria
interPolated
from 1897: Coctage
date
is
2L732 Dayville
(5) Starion closed Ocrober L972, daca to date
StaEion).
is
2292: Detroit
(4)
Station closed October
(compaEiblestation).
L978, daEa to
(5) Station opened June 196I,
station).
prior
A-8
data
is
2800t Falls
City
I
NW
(comPatible
(conPatible
August
I976,
Station closed
stations.
(8)
Statlon opened t{ay 1953, prior
station).
(9)
Starion opened Septernber 1965, prior
station) .
1959, prior
Srarion opened January
(compatible station).
(fl)
Station opened May 1969, prior
station).
(12)
Sration
(f3)
Srarion opened Novenber 1966, prior
(compatible station).
opened July
I973,
(15) Daca from July
data
(1?) Station opened August L967, prior
station).
8879: Vernonia
is
is
to date
known as 4430: Lakeside prior
to
2.
(compatible
8812: Va11ey Falls
is
data
data
(18) SEarion closed SePtember I971'
( c o m p a t i b l e s t . a E i o n ).
(19) Station
8410: The DaIles
196? through January I975 is
(15) Station oPened May 1965, prior
station).
Reservoir
7325: Roseburg WB City
is
data
wB City.
99462 Warm Springs
is
2 NW
(compatible
67612 Portland
data
(14) Station opened October 1955, Prior
(compatible sEation) .
8924t Sod House Voltage
is
is
data
4615: LaGrande (comPatible
6464: Parkdale
is
data
prior
is
data
data
(lO)
(compatible
1352: Canyon city
is
data
from nearby
interpolated
to date
data
(7)
(comPatible
5305: I'lerwin Dam
1958.
(20) SEarion opened l.tay1959, prior data is 138I: Chesaw through October 1958
and 1383 Chesaw 2 NE until May 1959 (compatible staEions).
Station
(22)
Srarion closed March 1972, data
(compatible station).
cfosed
May 1973, data
(23) StaEion opened in
Prior
3226: Goldendale
is
to date
November I967;
Cushman PoYrer House.
is
to date
(21)
daEa is
(24) Station closed August 197?, data to date
stations.
is
2 E
1485: Kalama 5 ENE.
interpolaEed
from nearby
from nearby
to date
is
interpolated
(26) Station closed SePtember 1978, data to date
(compatible station).
is
49?5: Marshfield
(25)
Station closed
staEions.
Septenrber I977,
data
(271 Station closed October 19?6; data to date
station).
(28)
Srarion opened September 1947, prior
stat ion) .
A-9
data
is
5I33:
7 W
Mazama(comPatible
Ls 7223: Ruff
3 SW (compatible
1959, known as 76993 Skagit
(29)
Prior
(35)
Sration opened in
Field).
(3I)
Station closed July
stat ions.
to
Poner (same station).
December 19AAi Prior
1977, data to date
A - l0
data
is
is
7483: Seattle
interpolated
fron
(Boeing
surrounding
APPENDIX B
DESCRTPTTVE STATTSTTCS (I949-L979)
- 244 STATIONS
SEASONAL AND ANNUAL PRECIPITATION
MONTHLY PRECIPITATION
43 STATIONS
(all
data in inches)
B-t
DESCRIPTIVE STATISTICS
S E A S O N A LA N D A N N U A L P R E C I P I T A T I O N
( 1 94 S - r 9 79 )
( oREGON)
Mean
ltledian
cv
rg
Percentiles
75
25
ANTELOPE
SL97
90
M a x( y e a r)
I ' 1 i n( y e a r )
L9.15
s.3A
15.gS
12.04
6.33
r6.69
r 3 . 6 7( 4 3 ) 2 . 3 8( 7 1 1
7 . 7 9 ( 4 8 ' , , s . 5 6( 74 l
19.62(48) 7.59(44)
rs.g9
t L L
8.73
2. 4 5
10.98
2.95
r2.39
r r . 6 6( 5 1 ) 1 . 4 8 ( 7 7 )
3 . 8 2 ( 4 8 ) s . 2 4( 4 9 )
r 4 . s 5 ( 5 r ) 4 . 4 3 ( 7 7)
12.34
2.65
15.36
r8.53
s.45
2 3 .t r
2 0. 4 9
7.29
25.36
2 3 . 4 8 ( 4 3 ) s . 2 2( 7 7)
8 . 5 6 ( 4 1 ) s .5t (7A',,
27.83(s6) 8.36(ss)
A S T O RE X P E R I I , I E NSTT A T I O N
0318
43.87
w
65.54 g.24
6 6. 4 2
7.72
r2.s4 9.32
s
12.39
5 7. 4 3
76.92 S.r9
78.8r
Y
59.99
9.25
69.72
75.49
14.94
89.69
90.95
t8 .22
99.83
9 9 .3 0( s 6 ) 2 8 . 4 2 ( 7 7 )
2 1 .s 4( 6 8 ) 6 . I 4 ( 6 ? )
r r . r . 7 4 ( 5 6 ) 4 5 . 5 r( 7 7 )
A S T O R I AW S OA P
9328
t{
61.15 0.22
6r.73
s
11.6s 0.31
1r.67
74.54 g.l9
Y
73.39
45.25
7.25
s7.36
54.16
I .94
62.75
69.16
14.27
81.21
75.75
r7.11
92.5r
9 s . 6 r ( s 6 ) 2 8. 4 2 ( 7 7 ' , )
r 9 . 7 7 ( 6 8 ) s.99(67)
r99.22(56',t 4 s .s l ( 7 7 )
AUSTIN3 S
13.96 5.25
14.80
5.15 0.31
5.55
1 9. 8 5 S . L 9
2 S. 3 5
TL.gg
3.45
1 5 .4 4
L2.45
4.s9
r7.22
17.51
6.35
22.88
19.39
7.53
2 5. 7 6
5 . 8 5( 7 7)
2 3. 2 7( 74 l
1 r . 6 2 ( 4 r ) 2 . 6 8( 5 r )
2 8 . s 2 ( 6 s ) 1 3. s 2 ( 4 A ' , t
B A K E RF A A A P
O4L2
w
5.89 5.28
5.86
4.44 0.32
s
4.58
16.15 s.24
L S. 4 4
Y
3.84
2.58
4.44
3.43
8.I5
7.33
5.55
I2.41
7;68
6.85
10.31(78) 2.46(771
7.47164l 1 . 8 r ( s r )
r 7 . 5 5( 7 8 1 6 . 3 0 ( s r )
w
s
Y
8.94
4.93
12.97
9.s3 0.29
3 . 7 7 g. 4 0
r3.s6 0 . 2 4
ARLINGTON
0265
7.1r
!.J
7.31
1.73
s
1.88
Y
9. 19
9.23
S3g4
w
s
Y
0.3r
-r.s2
76.22 s.29
3 . 9 9 s.49
25.83 9.25
9.7r
1.84
I 2 . 85
s356
h,
q
Y
4.66
a.4r
s.26
ASHLAND
rs.38
4.23
19.61
5.36
L.gS
8.73
6.25
/ . bJ
7.37
2.88
r9.77
5.6s
I .39
I
B-3
13.s5
(oREGON)
P e r c e n t i L' 1e 5s
25
90
I'tax(year) tlin(Year)
cv
Tg
s. 2 9
s.36
s.24
4.5s
2.50
8.09
5.37
3.52
9.s3
8.66
5 .5 5
13.12
9.s7
6.64
t4.23
1 1 . 8 9 ( 7 8)
r 0 . ? 8( s 5 )
r 9 . 2 s(s 6 )
BANDO}i2 NNE
9 4 7I
l,v
31.77 g.2g
53.06
6.87 5.3'l
7.11
S
6 s. 3 4 0 . 1 7
60.18
4 S. 4 1
4.24
48.11
4 7. 8 r
4. 9 I
53.34
58.75
8.62
67.59
6 4. s 4
L5.84
72.14
79.37(74) 22.53(7't)
13.48(53) 2.8s(65)
8 5 . 4 ' t( 7 4 ) 3 5 . s 9 ( 7 7 )
s.36
9.55
s.3r
5.91
1.18
7" 9 4
6.47
9.35
9.92
4.69
t4.34
13.36
5.35
16.66
r4.93(74)
I0.17(48)
2 5 . 8 7( A 8 )
1.38(77)
r.92(60l
4 . 3 s( s s )
9.29
0.38
s.2r
5 . 63
I .68
8.14
6.43
2.35
9.s6
9.35
4.13
12.55
10.97
5.L2
14.04
r2.83(78)
6.92(64)
16.74(6s)
1.6s(77)
r . 3 4( 4 3 )
6.22166)
B O N I i : " ' ;L L E D A I ' 1
a8 9 1
64.20 55.54 0.22
S
11.55 r1.48 s,30
I
75.'76 i6.34 0.r8
46.59
?.58
56.46
5s.74
9.22
6s.85
73.s3
13.31
85.94
81.58
I7.93
93.91
52.49
A.45
64.82
65.97
6.31
79.16
77.35
12.89
87.33
84.21
1 3. 9 8
94.51
9 2 . s 7 ( 5 8 ) 3 s. 6 3 ( 7 ' , t J
3.s4.(55)
19.27(s3)
98.96(78) 44.54(77)
5.65
1. 3 8
I .45
6.97
I .88
9 . 74
r0.6'1
4.27
13.39
11.74
4.79
1s.6s
1 2 . 2 4( 7 8 )
s . 6 6( 4 8 )
15.62(63)
1 . 9 8( 7 7 )
5 . 7 9( 7 4 )
5 . 9 7( 7 7 )
21.89
3.52
2 6 .s 8
25.3s
A.'t2
31.53
34.86
7. 2 A
4t.7r
44.L4
9.16
a-7.53
4 6. 7 S( 4 3 ' ,
r1.28(77)
s3.93(43)
lS ,55(7'l')
1.54'(?4)
21.83('77)
38.42
7.83
52.s5
46.55
8.28
56.14
56'.53
13.08
68.0s
64.58
15.25
73.78
72.581741 25.37(771
19.53(4r) 6.6'I(6s)
81.9s(43) 43.73(17)
Mean
0 111
h
S
Y
s694
S
M€iian
BAKER KBKR
b . b 6
4.68
11.37
0 . f 5
4.46
1S.91
BEND
8.58
8. 56
3.31
3.42
1].63
11.94
g 12 3
BEULA;
't
'7
.94
.87
3.24
3.39
\t.24
I r .17
1 0 5 5 B R C O !:( N GS
w
i i .77
6 9. s ' 1
9.49
78.55
I
9.25
8s.31
S.l9
9.42
S.16
1 r 7 6 B U R N ST { S OC I
w
I .46 s.28
8.60
Y
3.s8
1I.69
2.88
1r.57
0.43
5.22
BUTTE FALLS l S E
l2a'l
w
s.26
3 0. 5 5
2 9. 4 r
S
Y
6.95
35.56
1433
lri
I
0.35
0.2r
cASCrlI A
5r.s2
1 t
I t
6.s6
36.54
d A
. U !
62.s6
5 e. 4 6 s . L 9
9.29
' a
I 1
6I . 5 6
g.t5
B-4
2.3s(17')
2 . l 6 ( 6 1)
7 . 3 7( 7 7 )
9 3 . 5 7( 7 4 ) 2 0 . 4 8 ( 7 7 )
4 . 2 6( 6 1 )
1 9 . 6 7( 7 1 1
rs3.17(74) 5s.rs('771
( o R E G o N)
l,lean
f,ledian
CHEHULT
] 546
w
2r.64
29.26
s
4.34
4.13
Y
25.98
24.95
cv
Lg
Percentiles
75
25
90
I ' 1 a x ( y e a r )M i n ( y e a r )
s.33
g. 4 t
s.27
I3.80
2.92
t7.80
I7.26
3.r3
22.rr
26.4s
5.24
31.11
3g -34
7.O5
34.66
4s.tsl74)
3.87(77)
8.67(44) 1.s9(ss)
42.s2(74') 9.80(55)
1552
C H E R R YG R O V E2 S
w
48.31
49.15 s.2t
s
7.s8
6.23 0.36
Y
5 5. 4 0
55.58 g.r7
35.85
4.39
44.24
42.95
5.37
48.92
52.53
8.6'l
6r.39
59.23
Lg.6'l
64.38
74.9st74) r7.42(77)
r2.89(68) 2.46(67)
79.73114) 29.54(77)
E
9.33
9.44
0.26
8.62
r.85
11.54
Lg.5g
2.47
13.77
16.92
4.45
25.53
2L.95
6.57
24.49
2 2. 8 7 ( 6 s )
7.59177)
28.3r(s6)
1 6 4 3 , ' C L A T S K A N I E3 l r
w
49.97
49.47 9.22
s
7.66 s.35
8.47
Y
58.44
5 7. 9 2 0 . ] 8
34.53
5.59
44.62
45.58
5.32
52.12
54.86
10.15
65.48
64.96
13.I8
7r . 8 2
74.43(s5) 22.0t(77)
16.1?(78) 2.67(67)
83.30(56) 37.38(77)
5. 9 1
2.37
9.48
7. L 6
3.00
rI.S7
r g . 94
5.33
15.43
72.97
5.97
r8.S8
1 6 . 2 7( 7 4 )
8.42(48)
2 r . 3 6( 4 8 )
2 9. 9 3
4.33
34.67
3 9. 8 9
6.61
45.28
46.4s
8.47
53.24
63.7s(74) r4.18(77)
1r.8r(68)
2.4'7(67)
67.70(74) 2A.6s(77)
3s.ts
35.57
44.sL
3.67
37.s9
5.67
42.65
8.16
55.76
48.53
Ig.g9
5 6 .3 4
59.88(74) 1s.87(77)
r2.45(68)
3.05(7A',)
64.Ir(s6) 25.08(77)
I9O2
C O T T A GG
E R O V ED A M
w
40.I0
4s.5s s.22
s
?.35
7. 5 4 0 . 3 5
y
4 ' 1. 4 5
48.99 s.l'l
29.19
4.r2
37.07
34.36
5.61
41.85
44.3A
8.s8
51.75
5r.49
10.91
5 8. 8 6
61.12{?4) t'7.46(77)
14.34(68) 2.s8(s1)
6 4 . 4 7( ' 1 4 ) 2 8 . s 3 ( 7 7 )
1926
COVE
w
r4.75
14.65 S.2t
s
8 .1 4
8.51 S.33
v
22.89
22.19 S.I8
r1.68
4.99
r7.42
L3.97
6.57
2 g. 4 7
16.?9
9.'t7
25.77
t9.03
Ig.15
28.79
2t.25(',?8t 6.46(77)
1 7 . 3 0( 5 1 )
2.86(74)
30.3s(41) r3.r9(65)
1571
C H I L O Q U I NI
lri
14.19
14"35
s
3.67
3.24
y
17.86
18.38
CONDON
1765
w
9.33
9.15
s
4.I4
3.96
y
13.47
13.99
9.29
s. 4 s
9.25
1862
C O R V A L L I S - S T AU
TE
NIV.
w
35.24
33.19 0.25
25.5'1
s
5.51
5.40 5.39
2.93
Y
40.86 49.rS 9.22
31.97
1897
COTTAGEGROVE 1 S
3 9. 8 3
3 9. 2 4 g . 2 r
6 .93
6 . 7 2 S. 3 3
Y
4 6. 7 7
46.54 S.I?
irJ
D
B-5
2 . 2 3( 7 7 ' , ,
L . 2 9( 7 4 )
9.68(ss)
3 . 8 1( 7 7 )
].r9(49)
7.8o(49)
( oREGON)
Percentiles
Mean
M e di a n
CV
m
2
5
/f,
90
l i l a x( y e a r )
t ' 1 i n( y e a r )
1946
C R A T E RL A K E N P S H Q
l,{ 58.63
56.81 0.23
44.43
s
9.63
9.54 0.35
5.75
Y
68.26
67.51 g.l8
52.72
5A.41
7. 3 7
5r.s2
66.67
II.7S
78.36
78.36
13.12
87.39
8 s . 8 6( 5 1 ) t 9 . 7 4 ( 7 7 )
r 9 . 3 3 ( 7 7 ) 4 . 2 6( 74 )
9 r . s 9 ( s 1 ) 3 9 . 0 7( 7 7 )
2II2
DALLAS
w
44.41
45.98 5.26
s
5.82
5.57 5.37
v
5 0. 2 2
5 s. 9 9 s . 2 2
30.99
3.29
35.44
37.52
4.23
4 3. 4 2
5I.59
6.89
5 ' l. 3 0
57.9r
9.08
o5. /J
74,22(74) L7.02(77)
1 1 . 1 s { 7 8 ) 2 . 2 8( 7s )
7 7. 8 t ( 7 A ' , ) 2 4. 8 8 ( 5 5 )
2 135
DANNER
w
8.11
8.13 5.25
s
3.90
3.94 9.35
v
12.92 11.85 9.22
5. 3 9
2.Ss
8.97
6.96
2.89
10.13
9.ss
5.12
14.03
I9.56
5.59
1 5. 4 5
t2.32 169)
6.15 (52',)
1 6 . S 1( 7 1 )
2 . 5 2 ( 7 7|
r . 2 7 ( 74 )
5 . 9 3( 6 6 )
2168
DAYVILLE
w
7.61
7.93 g.3g
s
4.35
3 . 9 r g. 4 2
Y
11.97 1].12 s.27
4.87
2.49
8.r1
c, a2
3.26
9. 4 5
r4.3s
rs .37
6.49
15"63
1 3 . s 7 ( s 8)
9 . 8 9( 4 1 )
29.13(58)
3"s5(7'1',)
r.06(74)
6 . 9 7( 4 9 ' , )
69.28 0 . 2 2
I5.92 0.35
89.47 g.r8
51.54
6.82
62.14
59.66
9.s4
69.38
78.55
13.89
95.16
8 8 . 3 5 L s 2 . 1 8( 74 ) 3 r . 4 7 ( 7 7)
4.63(51)
18.33 22.s|(77)
97.r3 trz.s5(74) s3.48(77)
2406
DRAIN
w
41.28
40.87 o.23
s
6.11
6.12 s.34
Y
4 7. 3 9
46.82 9.20
3 S. 2 6
3.4A
3 7. 6 1
3 4. 7 0
4.47
4I.42
4 7" 3 9
7.99
53.77
54.77
9.15
59.31
6 s . 2 7 ( 74 )
1 s . 9 6( 7 9 )
6 8. 4 s ( 7 4 )
1 6 . 7 ' 7( 7 7)
2.21(73)
2 4 . 9 2( 7 7)
2440
DUFUR
w
9.63
9.39 s.3r
s
2.46
2.45 9.26
v
12.08
1r.64 0.35
6.29
t.L2
8.29
7.38
2.52
I0.24
TI.gS
3.23
13.73
14.45
3. 4 9
t7.34
r6.r9(74)
4.76(48)
1 8 . 2 0( s 6 )
2.t8177)
6.86(xx)
5 . s 3( 7 7 )
2633
E L K T O N3 S W
w
48.17
48.75 9.22
s
5.39
4.89 9.39
Y
53.55
53.28 s.2g
33.96
3.54
49.68
4r.28
3.75
47.96
55.99
6.52
65.8s
59.s4
8.74
6 5. s 7
7s.s8(s6) 19.96(77)
9.83(71) 2.98(74)
7 9. 6 4( s 6) 2 3. 9 s( 7 7)
2672
ENTERPRISE
w
6.84
6.69 s.27
s
6.41
6.54 9.29
Y
13.27
t3.s5 s.22
4.55
4.57
9.94
5.72
5.30
ts.92
7.98
7.48
1 5 . 86
9 .s 9
8.53
t 7. I 7
r 9 . 5 8( 4 2 )
I 9 . 7 7( 7 7 )
1 9 . 4 2( s 6 )
4Zt t
w
s
v
8.84
5.24
uttxult
68.77
11.60
86.37
ts-6
2 . 3 s( 7 7)
r . 1 7( 7 4 )
7 . 5 7( 6 6 )
(oREGON)
l{ean
Med i an
cv
Tg
Percentiles
75
25
9A
l , l a x( y e a r )
l'1in(year)
ESTACADA 2 S E
2693
9.22
a6.24
w
48.02
LS.5A g.3s
s
I1. S0
s.r7
59.2L
59.52
v
35.75
6.94
47.98
42.15
8.66
55.79
5 4. 1 7
13.46
66.32
63.78
16.20
73.94
6 e . 3 2 ( 5 6 ) 2 2 . 6 6( 7 7)
4 . 2 3( 6 7)
t7.44(771
7 6 . 9 8( 5 6 ) 4 9 . t o ( ' 7 7)
E U G E N EW S OA P
2709
36.96 5.26
t{
38.12
5.54 g.4g
s
5.87
42.67 g.23
43.99
Y
27.49
3. 3 1
33.52
32.t7
3 . 93
38.26
43.68
7 . 8r
48.66
50.24
9.24
57.92
7s.82(74\
1 2 . 2 5( 6 8 )
7 4 . 1 8( 7 4 )
FALLS CITY 2
2855
65"8? 9,26
w
64.64
6.72 0.49
s
6.99
72.65 9.23
71.54
Y
42.5'7
3.15
5A.70
52.82
4.79
62.79
74 . 7 5
9.A9
81.16
99.94(14)
86"9s
1 2 . 4 9( 4 L )
TO.5A
9 2 . 5 5 r s s . 7 L ( 74 )
F O R E S TG R O V E
2997
39.48 9.22
v{
38.71
5.55 9.36
s
5.92
44.96 0.r8
44.63
Y
28.72
3.43
34.46
33.34
4.58
39.26
43.56
6.49
5 A. 9 3
48.97
9.36
54.9r
14.3s(77)
5 9. 2 8 ( 74 l
1 2 . 2 4 ( 6 8 ' , t 2 . 5 9 ( ' ts )
6 2 . 7 7 ( 7 4 ) 2 5. 2 r ( 7 7)
FREMONT
3095
7. 8 9 g. 4 6
w
8.18
3.19 g.a2
s
3.25
I0.79 s.3r
t1.43
Y
4.93
1.46
7.59
5.69
2. 3 7
8.65
r0.59
4.50
13.79
12.26
5.16
rs.4t
1 5 . 1 7( s 6 )
6 . 7 7( 6 6 1
2 I . 94 ( 5 6 )
r.9I(77)
0 . 8 4( s 5 )
3.53(5s)
FRIEND
3I21
13.53 0.28
l{
r3.83
2. 8 1 o. 4 0
2.82
s
1 6 .3 7 s . 2 6
1 6. 6 5
Y
9.55
I .49
rr.14
r1.44
2.55
13.72
17.14
3. 5 1
19.11
r8.48
4.29
22.67
2 3. 5 3 ( 4 6 ' , '
5.25(48)
2 6" 4 9 ( 4 3 )
4.12(77)
s . 6 8( 7s )
8.88(77)
G O L D B E A C HR A N G E RS T A T I O N
3356
56.38
70.98 S.2L
l{
71.94
4.s5
8.s9 s.44
s
9.58
6 7. 2 9
8 S. 2 5 S . r 8
Y
8 9 .? 8
62.16
5.11
73.44
I r .99
r3.56
92.86
88.79
15.45
98.24
CAMP
GOVERNI'IENT
3402
72.86 5.23
w
72.45
15.56 9.25
s
15.52
8 7. 9 1
99.10 0.19
v
5L.09
1 9. 8 5
66.92
61.31
13.4s
74.15
81.84 95.83
2L.39
16.96
97.29 111.s5
rs9 .32 ('t A',t 3 8 . s 5 ( 7 7 )
2 4 . 3 8 ( 3 1 ) 5 . 2 9 ( 5 7)
t24.27 (74) 65.7r(771
G R A N T SP A S S
3445
w
28.33 s.29
28.08
3.72 0.5s
s
3.73
33.12 0.25
Y
3r.82
16.6r
I.2S
2s.27
22.62
2.39
26.58
32.94
5 .1 5
3 6. 8 1
37.25
5.82
4 s. 6 5
4 8 . 3 1 ( 7 4 ) 8 . s 4( 7 7 )
s . 4 7( 74 )
7 . 7 8( 4 7 \
s1.25(s6) 16.s5(77)
B-7
1 0 6 . 3 2( 74 )
2 s. 5 8(5 3 )
t L s . 4 4 ( 74 l
16.73(77)
2 . 4 9( 6 5 )
2 3 . 7 4 ( ' 7 7)
2 2 . 1 A( ' 7 ')t
2 . 1 2( 6 7 ' , )
32.3't(77)
2 9 . 7 6( 7 7 1
3.77(6s)
46.23(77)
(oREGON)
Percentiles
Mean
t0
lted i an
25
75
9g
l i l a x( y g a r )
Hin (year)
GRIZZLY
3542
w
8.99
8.89
4.27
s
4.4s
Y
13.35
1 3 .1 3
s.27
s.44
s.24
s.65
2.Sr
8.60
7.68
3.r3
1r.35
10.56
5.54
15.77
T2.T7
6.79
L6.79
13.16(st)
9 . 4 9( 4 1 )
2r.54(48)
2.58(77)
S . 7 o( 4 9 )
7.36(77l-
HALFWAY
3554
w
16.55
16.23
s
4.74
4.49
Y
2I t29
2I .24
0.25
0.32
o.2t
1 1. 9 9
2.9'l
15.87
1 4. 7 1
3.81
19.96
19.5r
5.6s
24.23
2I.T7
6.14
26.66
2 4 . 3 s ( 74 )
9.84(4r)
29.86(s8)
3 . 4 9 ( ' 1 7)
2.22(74)
e.46('t7)
NE F U G E
3692
H A R TF 1 O U N T A IR
w
3.97
6.44
6.31 5.33
s
2.4t
4.29 5.40
4.61
?.83
Y
1 1 .S 5
IS.r2 9.27
4.83
3.39
8.78
7.46
5.6s
13.59
9. 3 7
7. 6 2
15.67
11.83(63)
8.94(6s)
1 8 . 1 3( 6 3 )
2.35(77)
r.5S(74)
7 . 4 7( 4 6 )
W A T E RB U R E A U
H E A D W O R KP
SO
, RTLAND
3779
w
64.82 0.20
5 9. ' 1 4 5 9. s 0
66.45
s
10.56 13.84
1 6 ,1 3 0 . 2 7
16.69
'12.98
Y
66.57
83.1s
82.26 o.16
73.93
84.37
1 9. 5 1
2 2 . 7L
91.73 1O2.25
HEPPNER
3827
l.l
9.4s
9.61
s
4.35
4.44
Y
13.79
t4.95
3847
w
s
v
s.25
0.39
s.2s
6.3s S.3r
2.15 9.46
8 . 8 8 g. 2 5
HILLSBORO
3968
t{
31.98
32.45 0.2I
s
5.96
5.82 0.35
Y
37.94
31.62 0.r7
7.3r
3.38
12.23
Ir.g4
5.42
I 5.81
12.38
5. 9 1
I7.93
1 5 . 1 3( 7 4 )
9 . 6 s( 4 1 )
2s.63148)
? . 8 6( 7 7 )
r.3g(4s)
9.26(77)
4.46
). z5
9.gg
2.46(77)
s.64(6'7)
5.48(77)
s.9r
6.r5
t .51
7.53
8.55
2.97
I0.31
3.65
12.r1
12.90(741
s.03(48)
r3.8S(s8)
24.44
3.7s
2 9. 5 5
28.04
4.46
33.41
35.9s
6.74
42.5L
41.19
8.84
46.29
47.92(74) 11.35(?7)
1 . 9 7( 6 7 )
1 1 . 3 4( 6 8 )
5 t . 9 2 ( 74 ) 2 2 . 5 8 ( 77 )
3r.33
4.8r
36.40
35.25
5.53
38.52
4 2 . 74 ( 7 A ' , ) 7 . 8 4 ( 7 7 )
0 . 9 5( 6 7 )
9 . 5 9( 5 3 )
','
45.69l74) r3.6s (77
rs.8r
L2.42
4.88
16.3r
16.r9(78)
5.35(70)
t8.76(78)
4Sg3
H O O DR I V E R E X P E R I M E NSTT A T I O N
1 7. 6 4
2r.84
w
26.59
2 5 . 7 9 S. 2 7
s
I.97
2.86
3.90
3.55 5.46
v
2r.92
24.79
30.49
35.89 5.23
Ag98
HUNTINGTON
l{
8.96
9.s4 S.3S
s
3.68
3.r2 9.43
v
12.95
t2.24 0.26
32.74117)
7.55(67',)
5 7 . 6 2 ( 7 7)
6.83
2.13
9.5s
H E R M I S T O N2 S
6.69
2.31
9. g a
1 s 3 . 7 1( 4 3 )
2 6. 9 9 ( 4 r )
r2s.s2(A3)
5 .5 8
r.21
7. 4 9
7.44
r.92
9.76
B- 8
4.Q4
14.34
1.95(77)
s.8s(66)
s.93(66)
(oREGON)
Percentiles
cv
Lg
25
4133
I LLAHE
w
77.97
78.83
s
7.51
6.8r
Y
8 7. 5 2
86.34
s.23
s.46
0.2s
57.59
4.54
64.68
69.44
4.53
76.L2
r O N E1 8 S
416r
w
8.6r
8.79
s
3.68
3.88
v
t2.67
t2.86
o.3s
o. 4 3
s.26
5.58
r.72
8.65
7.13
2 . 7r
9.99
JOHNDAY
9.85 s.28
9.27
4.95 5.29
5.52
1 4 . 3 4 A. 2 3
14.29
5.62
3.24
9.48
KENO
44A3
l{
15.97 0 . 3 r
15.55
s
3.89
3.4A s.42
v
19.44
19.69 9.24
Mean
l.ted i an
75
9g
t{ax(iear)
Min(Year)
92.59 99.54
12.79
rs.s3
9 6 .s 8 t a 9 . 5 2
rr2 .99 (7 4')
1 s . 3 9( 5 3 )
rrs.8o(74)
2 8. 2 5 ( 77 )
2.8L(7A',t
4r.74(17)
rs.79
5.97
t4 .5s
r1.85
5.52
1 6 .3 r
15.76(48)
9.S3(48)
2 4. 7 9 ( 4 8 )
r.74(77',t
5.64(74)
6 . s 4 ( 7 7I
7.s5
4.gr
1 1. 9 8
1I.19
5.8s
1 7. 2 5
12.13
7. 9 3
18.27
14.97(s1)
8.71(6s)
2 5 . 6 9( 4 8 )
3.18(77)
2.38(77)
7. rs (73)
9.19
2.57
12.65
L2.47
2.8r
I6 .68
19.15
4.79
22.92
2L.54
6.69
25.94
2 5 . 4 5( 74 )
7.6r(77'
2'7.70(7I'
4 . 9 4 ( 7 7)
1.37(55)
8.64(55)
5.24
1.57
7.85
6. 4 5
2.3r
8.96
9.69
3.89
13.22
11.82
4.67
15.25
L 2 . 3 3( 74 1
7 . 7 8( 4 8 )
1?.89(78)
2 . 3 9 ( 1 7)
s . 8 9( 6 7 )
6.32(77)
4506
K L A M A T HF A L L S 2 S S W
w
6.44
19.72
ts.84 0.33
r.38
s
3.1r 5.49
3.3s
v
8.74
14.62
13.97 5.27
7.54
2.02
t1.37
13.15
4.19
I6.71
14.96
s.65
19.s2
18.35(s6)
7 . 5 4( 4 8 )
22.79(56)
2.4s(7't)
0.72('7s)
7.52(ss)
4622
LAGRANDE
w
13.73
13.75 s.22
s
s.87
5.83 g.3s
Y
19.59
19.61 s.r8
9.89
3.73
L4.72
12.08
4.95
r7.94
1s.71
6.72
22.27
17.55
7.s3
2 3. 4 6
18.97(48) 5.69(77)
2.83(74)
r2.84(41)
2 7 . 5 7( 4 8 ) r s . 4 0 ( 7 3 )
L A K E V I E W2 N N W
4679
l{
11.41
11.52 5.29
s
4.33
4.1r 0.38
v
15.73
15.58 9.24
8.12
2.38
I r .08
8.95
2.94
13.60
13.6I
5.52
1 8 .S 5
15.93
6.45
2r.46
17.84(7r)
8,25(71)
2 3 . 8 6( 6 3 )
481.I
L E A B U R GI S W
1 { 5 1. 4 8
50.62 0.20
s
10.15
9.64 5.29
Y
5r . 28
6 2 . 4 9 A. 1 6
37.48
6.24
49.13
44.47
8.13
53.59
57.64
12.59
67.6r
66.00
t4.92
75.97
74.65(?4) 23.80(77)
4.3I(67)
rs.62(4])
8 0 . 6 9 ( 7 4 ) 3 8 . 6 8( 7 7 )
A29T
w
D
Y
KENT
44]1
w
7.87
8.14
s
3.24
3.33
Y
11.38
1r.05
9.29
s.43
s.25
B- 9
2.36(77)
I.37(45)
6.98(77)
( oREGON)
Percentiles
Hin(Year)
Tg
25
75
90
M a x( y e a r )
HAYCREEK
5S8O LOWER
6.18 5.32
w
7.14
3.27 9.42
s
3.r8
10.33 r9.37 5.26
Y
4.22
1.48
6.s9
5. 5 7
2.16
8.57
9.lg
4.gl
12.16
r0.73
4.90
13.95
1 1 . 3 2( 4 3 )
5.7s(48)
16.10(48)
1 . 6 6( 7 7 )
s.57(74)
5.46(77',)
IIADRAS
5139
w
6.65 9.32
6.84
3 . 1 5 s.44
s
3.14
9 . 9 8 o. 2 7
Y
9.98
4.45
I .48
6. 3 7
5.16
2.33
8.25
8.68
3.93
11.34
9.17
4.68
lA.g2
11.31(78)
6.83(48)
15.s2(48)
r.42(77)
5.48(49)
4.64(77',t
Mean
l,ledian
CV
M A L H E U RB R A N C H E X P E R I M E N T S T A T I O N
5169
4.46
6.ls
7.92 s.27
w
6.98
s
Y
2.89
9.87
2.91
9.99
9.42
5.23
I ' I A L H E U R E F U G EH D Q
5162
w
5.71 5.34
5.87
s
3.33 0.36
3.42
v
9.29
9.47 9.24
r.44
7. 9 7
r.90
8.77
8.r5
3.62
TI.42
8.86
4.45
L2.24
1 r . 9 0( 7 8 )
6.s3(41)
14.72(4r)
2.r7177','
s.78(66)
4 . 5 9( 5 6 )
3.23
1.93
6.52
4.78
2.57
7.37
7.45
3. 9 1
r9.67
8.41
5.6I
12.43
9.53(78)
6.s2(76)
1 3 . 4 7( 7 8 )
1.s](77)
1.67(69)
s . 1 8( 5 0 )
M C K E N Z I E B R I D G E R A N G E RS T A T I O N
5362
44.74
51.15
w
59.s9 0.22
59.32
Ls.57 0.39
69.26 0.r7
6.39
55.96
8.45
61.41
57.86
12.72
78.65
76.79
15.61
85.63
84.54(43) 25.32(77)
5.32(52)
1 9 . 2 s( 4 I )
95.82(43) 4r.55(77)
5384
MCMINNVILLE
w
3 7. 2 4
3 7. 6 5 5 . 2 4
s
5.82
5.29 S.4g
43.sr g.25
v
4 3. 6 6
28.r2
3.52
32,98
32.12
4.28
37.3s
4r.97
7.r7
48.52
49.08
8.87
56.13
s 6 . 9 8( 7 4 ) 1 3 . s I ( 7 7 )
12.28(68) 1.74(6s)
6 s . 2 3 ( 74 ) 2 3 . 3 8( 7 9 )
E X P E R I ! { E N TS T A T I O N
MEDFORD
5424
12.8r
1r.14
t{
1 7 . 1 1 1 7. 9 3 0 . 3 2
2.55
1.56
s
3.85
3.62 5.49
14.3r
16.58
v
29.32 9.26
29.96
29.r7
5.24
24.91
22.52
5.6'1
28.r9
34.74(14) 5.35(77)
8.47(7'7) 0.58(74)
3s.32(74) r0.68(55)
M E D F O RW
D S OA P
5429
w
16.49
16.69 g.3g
s
3.s6 5.52
3.48
Y
19.97 19.28 0.26
s
'I 10 9. 7. 935
ItlILTON FREEI{ATER
5 593
w
9.77
9.82 5.26
s
4.13
4.99 5.37
13.75 g.2g
Y
13.9I
11.21
1.35
13.3r
13.15
2.26
16.43
19.77
4.53
23.82
23.83
6.31
26.13
2 7 . 5 9( 5 6 )
7.7r(77)
3 4 . 4 s( s 6 )
4.74(77)
5.32(74)
8 . s 4( s 5 )
5. 36
2.48
9.33
8.66
3.15
12.02
r1.1S
4.99
1 6 .1 S
13.s4
6.41
I - 1. O 5
l4;85(74)
8.7s(4r)
19.87i48)
3.93(77)
r.49(49)
8.79(64)
B-10
(oREGON)
Percentiles
llax (year)
Min (year)
cv
Lg
25
75
9g
g.3r
s.39
9.25
5.58
r.27
7.75
7.55
2.Sr
9.65
Ir.gg
3.29
13.67
12.37
3.79
r5.80
r4.48(s1)
s.13(77)
r1.s6(48t
NEWPORT
6532
w
59.96
58.34 9.22
s
19.35
9.37 s.38
Y
70.31
69.26 s.19
44.23
s.39
54.92
s1.34
8.rl
6s.86
68.61
11.51
81.24
76.63
15.54
88.91
89.31(74) 26.7s(77)
23.s3(68) 3.5s(52)
99.r4(74) 42.76(77)
NORTHBEND FAA AP
6973
w
54.44
55.82 S.r9
s
7.26
6.51 s.38
y
6I.7s
62.02 S.16
41.75
4.r7
47.7r
47.33
5.21
54.51
61.65
9.07
68.2r
64.15
tr.62
74 . s 6
7 9 " 3 6( 74 t 2 2 . 9 0( 7 7|
13.00(7r) 3.26(6s)
83.08(74) 32.75(77',)
4.32
r.49
6.6s
5.92
1.93
8.54
8.41
3.74
11.95
9.68
4.sl
13.29
1r.71(58)
6.43(41)
r4.92(41)
O A K R I D G EF I S H H A T C H E R Y
6213
w
2'7.67
38.18
37.11 0.23
s
7.64
4.59
7.61 0.30
Y
45.82
47.54 s.L9
34.36
32.56
s.84
39.79
43.76
8.96
5A.9r
49.70
rO.9s
58.28
5 8 . 8 I ( 7 4 ) 1 5 . 5 7( 7 7 )
12.35(78) 3.7r(74)
6 2 . 5 2 ( 7 4 ' t 2 6 . 9 3 ( 1 7)
R A N G E RS T A T I O N
6243
OCHOCO
w
13.26
I .68
13.36 9.28
s
4.97 5.42
5.31
3.03
Y
18.57
r3.34
18.37 s.23
rr.42
3.87
14.95
15.29
6.85
2r.37
18.24
I .43
25.23
3.92(77)
2 2 . 4 0( 4 3 )
1.43(49)
rr.2s(48)
26.49(48) 11.rS(73)
lrlean
lrledian
!!ORO
5734
w
I .92
8.69
s
2.63
2.52
v
1 1 .5 5
LI.g7
6179
w
s
v
NYSSA
7.t7
2.88
lg.g4
7.2s 9.30
2.55 s.43
9.95 s.24
2.t2(77)
0.7s(7s)
6.46(73)
9.9s(66)
s.95(66)
4.26149)
6495
OWYHEEDAM
l{
5.6s
5.44 s.32
s
3.28
3.29 o.49
Y
8.89
8.88 9.27
3 .1 0
1.45
6.2A
4.48
2.49
7.s3
6.75
4.18
L5.45
7.82
4.95
11.84
Ls.st(78)
6 . r . 2( 6 s )
1 4 .s 0( s 7 )
r.94 (77)
1 . 1 3( 6 6 )
3.9r(66)
6426
PAISLEY
w
6.89
6.12
s
3.72
3.38
Y
19.51
9.85
s.3s
4.93
r.56
7. 3 s
4.94
2.54
8.03
8.24
4.99
11.84
9.9r
5.78
1 4. 4 5
15.07(s6)
8.32(48)
19!48(56)
1.33(77)
0.85(7s)
s.64(72)
ssE
s.26
s.39
s.26
23.33
2.48
2 7. 7 8
35.54
3.18
35.24
45.18
5 . 94
5s.43
5 9. 3 7
7.20
54.91
6 2 . 5 7( 4 3 )
9.21(48)
6s.s9(43)
6468
P A R K D A L E2
w
37.31
3 7. 6 s
s
4.66
4.85
Y
42.96
43.48
o. 4 s
0. 4 7
B-l 1
8.78(77)
s.59(67)
r4.69(77)
(oREGON)
Mean
lledian
cv
Lg
Percentiles
75
25
9g
I { a x( y e a r )
} 1 i n( Y e a r )
P E N D L E T OW
N S OA P
6546
w
9.15 9.26
9.a7
3.A9 0.A4
s
3.48
12.25 0.2r
1 2 .5 5
Y
6.92
r.83
9.L0
7.43
2.r5
r0.87
L0.37
4.15
14.21
12.s6
5.47
16.45
r5.4s(74)
8.12(Art
r8.4s(78)
3 . 9 8( 7 7 )
r.3s(74)
7.67(68)
P I L O T R O C K1 S E
6634
w
9.56 9.26
9.56
4.44 S.38
s
4.55
14.97 5.27
Y
14.1r
6.53
2.51
9.63
7.97
3.40
t2.38
11"49
5.4s
t5.92
12.57
6.74
18.29
14.5S(48)
10.32(Atl
2 2 . s A( 4 8 )
4.18(77)
1.66(74)
I . 7 9 ( 73 )
6749
PORTLANDKGW-TV
!{
35.51 5.23
35.99
6.67 9.31
s
7.28
43.35 s.18
v
43.26
25.23
4.gg
33.rS
3I.ss
5.62
37.81
4 s. 7 9
9.22
49.98
46.36
11.13
54.27
5r.5S(56) 12.92(77)
2.94(67)
t4.69(771
5 8 . s 9 ( s 6 ) 2 7" 6 r ( 7 ' l )
POWERS
6820
l'/
53.92 s . 2 2
5 4. 5 6
s
5 . 7 9 0.46
6.45
59.82 s . 1 9
v
6r.sa
39.75
3.3'1
44.99
47.40
4.11
53.55
63.2r
7.36
68.35
65.75
r1.39
73.72
85.50(74) 23.33(77)
2.45(75)
14.90(s3)
88.22(74) 35.13(77)
PRINEVILLE
6883
w
7.16 9.32
6.83
3.69 s.39
s
3.61
v
r 0. a 4 r s . 8 0 9 . 2 5
4.45
I .81
6.95
s.36
2.65
8.49
7. 6 7
4.57
1r.97
9 . 93
5 . 65
13.95
11.85(78)
6.69(4rt
r 6 . 2 8( s 8 )
P R O S P E C2T S W
6957
w
35.45 0.27
35.58
6.58 g.As
s
6.22
49.35 s.21
4r.80
v
23.85
3.r3
28.98
29.98
4.s9
36.98
42.s\
7. 2 9
49.34
4 8. 6 3
9.4s
53.86
58.s7(74) 12.32(77)
12.3t(7'7l. L.12(74)
59. r9 (74) 24.63(77',)
R E D M O N2D W
1952
w
5.31 9.36
5.51
2.77 s.49
s
2.82
8.1r s.3r
Y
8.33
3.13
1.11
5.26
4.56
I .91
6.75
6.78
3. 5 6
9.56
8.r5
4. 6 8
12.45
9.83(78)
6.72(48)
13.5S(48)
REEDSPORT
7682
w
66.48 g.2g
6 6. 2 6
9 . 5 6 0. 3 7
s
9.65
15.37 g.r7
75.91
Y
5 2 .3 1
5.19
6s.87
58.71
6.8A
67.78
72.99
r1.80
83.03
7 7. 8 6
14.65
89.28
1r1.20(74) 26.33(771
3.86(66)
t7.8s(56)
116.43(74) 38.25(77)
25.6s
1. 7 3
23.65
2 3 . 8I
3.01
26.96
3 1. 0 9
4.66
3s.2s
35.48
6.81
38.82
9.35(17)
4 7. 3 5 ( 1 4 )
L . 5 o( 7A ' , '
7.5r t77)
48.8s(74) r6.85(77)
.7
I69
w
s
Y
RIDDLE
26.79
27.66
4.07
3.98
3l .35
3 1. 6 4
s.25
g.42
s- 2 r
B-12
t.45(77)
s.'72174)
5 . S 8( 5 s )
r.22('17)
.s2(ss)
1.7s(5s)
( oREGON)
Flean
iied i an
cv
Tg
Percentiles
75
25
9g
l j l a x( y e a r )
Min (year)
RIVERSIDE
7298
w
5.76 9.30
5.98
s
2 . 8 7 g. 4 9
3.r1
Y
9.68
9.r7 0.25
4.59
1.83
6.23
4.76
2.14
7.34
6.97
4.s4
L5.57
8.34
5.s7
11.94
L0.32(7sl
s.79(41)
r 3 . 8 8( 4 r )
7259
R O C KC R E E K
w
14.99
L5.22 s.24
s
6.47
6.42 0.29
Y
2I.46
2I.04 o . 2 g
r0.38
4.11
1 5 . 7A
13.s5
4.95
r8.98
16.46
7.46
24.s3
19.96
8.?6
3 7 .s 5
3 . 3 7( 7 7 )
2I.86(74)
13.71(41) 3.4s(74)
3S.41(s6) Ls.75(77',t
R O S E B U RKGQ E N
7331
l{
28.49
28.3s s.25
s
4.69
4.52 g.4l
Y
33.1S
3 2 . 8 8 S. 2 2
29.9A
2.27
23.96
23.28
3.06
2 7. 8 7
33.2s
5.79
37.93
37.56
7.35
42.45
45.86(74'' rs.43(77)
9.53(47) 1.73(65)
49.86(56) 18.49('t't)
7 354
R O U N DG R O V E
!{
12.88
12.58 g.3S
s
5.19
5.22 9.38
v
r8.g'7 17.41 g.2r
8.37
2.68
13.34
rs.s6
3.67
r5.69
16.68
6.37
25.41
17.89
7.81
23.44
19.96(56) 3.72(77)
r.53(72)
|s.93(77)
26.88(s6) 10.4s(55)
7 5 O O S A L E MW S OA P
w
34.50
35.23 9.23
s
6.94
5.74 5.33
Y
4A.54
45.68 S.I9
26.33
3.54
3l . 33
28.92
4.92
34.56
38.62
7.L2
45.s3
43.93
8.58
52.12
5 4 . 9 8( 7 4 ) 1 1 . 5 6( 7 7 )
3.97(52)
11.79(68)
5 8 . 4 8( 7 4 ) 2 s . 3 7 ( 7 7 )
764I
SEASIDE
w
63.86
63.63 S.19
s
Ir.91
12.59 9.34
75.78
Y
74.75 5.16
49.3s
7.35
62.22
57.69
8.44
67.24
7r.77
r4.22
82.77
79.38
1 8 .l 2
95.97
8929
S Q U A WB U T T E E X P E R I M E N T
STATION
w
7.43
7.23 g.3S
4.87
5.91
s
3.87
3.63 0.44
1.99
2.58
Y
1l-30
11.43 s.25
7.73
8.82
9.31
s.Is
t 2 . 76
10.14
6 .t 9
1 5. 8 1
12.71(58)
8 . 4 7( 4 7 )
1 7. 5 2 ( 4 8 ' , )
2.r7(7711 . 1 s( 6 2 )
7.02 (59)
8407
THE DALLES
w
I9.34
70.30 s . 3 9
s
1.92
1.91 s.44
v
12.26
1r.96 9.34
7. 3 1
r .40
9.Ot
t2.95
2.25
t5.90
r5.s3
2.83
r7.96
1 9 . 4 7( s 6 )
4.67(48',)
21.56(s6)
r.48(77)
. 3 s ( 74 )
4.43(77)
40.8r
5t .12
7.85
9.25
s 3 . 7 3 . 6 1. 1 4
67.58
13.s7
78.32
?5.77
15.95
87.96
8466
T H R E EL Y N X
w
59.42
59.55 s.24
s
11.33
Is.34 9.28
y
79.75
71.8s 0.18
5.69
.99
7.20
B - l3
9 2 . 4 s( 5 6 )
20.58(4r)
r a s . 0 3( 5 6 )
9 5 . 9 8( 7 4 )
]8.48(77)
L 0 5. 3 9 ( 74 )
1.1s(77)
1.13(74)
4.23(77)
2 6 . 2 5 ( 7 7|
5.13(67)
4 5 . 0 5 ( ' t7 )
25.84(77)
5.42(67)
4 4 . 3 2 ( 7 7)
(oREGON)
Percentiles
M e di a n
llean
I
TILLAI,IOOK
8494
w
75.96
76.69
s
14.12 13.34
88.78
v
90.81
cv
W
g.r9
5.36
S.r5
TO
25
75
9g
M a x( y e a r )
103.43(56)
2 8. 6 0 ( 4 r )
1r8.6s(74)
lilin (year)
36.32(77',|
5.37 (67',)
59.28(77)
59.59
7.5I
74 . 5 8
69.r7
r9.88
83.s9
95.02
86.17
1 7 . 1 4 2I.64
9 9. 5 7 r s g . 6 b
8.6s
3.2s
12.59
1 9 .r 6
4.24
15.22
r3.98
6.59
19.67'
1 5" 6 5
7.94
22.98
18.97(48) 5.56(77)
1 3 . 8 4 ( 4 1 ) 2 . 7 7( 7 4 )
27.88(48) 1I.49(77)
8746
U N I O NE X P E R I M E NSTT A T I O N
5.51
w
8.18
8.43 0.23
3.73
s
5.82 0.31
5.9S
ra.2r
13.82 g.2r
Y
14.08
7. 3 7
4.82
L2.52
9.41
7.A1
15.67
Lg.2s
7.82
17.73
r1.s1(58)
1 2 . 3 7( 4 1 )
2r.47(4I)
3.24(77)
2 . s 8( 4 9 )
8.25(66)
8.14
4. 9 7
12.53
9.14
5. 6 1
13.94
r0.L2(65)
7.87(41)
1 7. 9 2 ( 6 5 ' , t
2 . 1 9( 7 7 )
1.96174)
6 . s 8 ( 73 )
8.88
7.4r
3 . 9 9 4 . 7r
11.16 12.13
12.64(78)
5.24(64)
14.09(78)
I.96(7-t)
s . 7 8( 4 9 )
3 . 6 1( 4 1 )
1 6 . 8 8( 5 3 )
9.3S(6s)
22.6r(63t
2.82(77')
1.86(sr)
6 . 5 o ( 6 8)
8 ' l 2 , 6 U KI A H
w
12,20
12.A7 5.23
s
5. 7 2 9 . 3 7
5.56
Y
1 7. 8 5
1 8. 0 4 s . 2 r
8780
UNITY
w
6.88 s.28
6.70
4.98 0.33
s
4.15
v
1 0. 8 5
]S.98 s.24
4.14
2.53
7.Ig
s.39
3.21
8.93
8 ' 79 7
VALE
w
6.47 g.3r
6.46
2 . 8 8 g. 4 r
s
2.95
Y
9.36 0.25
9.41
3.82
r.41
6.69
5.55
2.93
7.88
8818
V A L L E YF A L L S 3 S S E
w
8.84 5.36
9.55
s
4.38 g.4l
4.6't
13.54 5.28
Y
14.21
5.55
2.35
9. 4 2
7. 4 5
3.29
11.68
s.22
g. 4 r
s.L9
7 8. 5 7
8.13
92.96
9 7. ' 1 7
9.96
r11.26
0.23
9.38
9.79
2 9. 4 5
4.24
35.56
3 5 . 84
5.36
42.55
45.96
7.90
5 4. 4 3
52.79
11.1?
59.64
6 2 . 4 4 ( 7 A ' , ) L 7 . 9 7 ( ' 1 7)
13.4r(58) 2.rS(521
6 7 . 7 2 ( 5 6 ) 2 9 . s 8( 7 7 )
11.71 9.24
6.06 s.27
18.25 s.L8
8.59
4. 4 r
1 4 .r 3
1s.55
5.25
16.gg
14.33
7.33
2 g. 9 8
15.9s
8.39
22.9r
1 5 . 9 0( 6 s )
1 2. s 8 ( 4 1 )
23.71(s6)
VALSETZ
8833
w 110.36 r59.72
s
15.24
15.16
Y 125.61 r24.58
V E R N O N I A2
8884
tll
{1.68
41.23
s
6.48
6.95
48.63
Y
48. 18
8997
w
s
Y
11.09
s.69
15.75
r23.64 t4s.87
24.86
18.03
1 4 5 . 1 4 1 5 7. 8 5
WALLOT'JA
r1.98
5.35
18.32
B-14
15.01
7. 6 3
19.79
1 6 6. s 2 ( 7 4 ) 5 3 . 2 - 1( 7 7)
3 s . 4 4 ( 7 8 1 3 . 6 9( 5 7 )
18r.92(74) 78.r4(77)
3 . 5 4( 7 7 )
2 . ' t r ( 74 )
tr.72(7'1',)
(oREGON)
M ea n
cv
WASCO
9A68
w
s
Y
M e di a n
8.95
2.48
11.43
9.r2
2.57
rr.6g
0.39
s.38
s.24
W I C K I U PD A M
9315
w
17.98 s.30
16.]r
3.89 s. 4 3
s
4.2s
20.94 0.25
v
2s.3I
Percentiles
75
25
LO
6.s3
I .39
7.95
t s .r 3
I .86
1 4. 0 4
9g
! 4 a x( v e a r )
Min (Year)
6.67
1.86
8.79
ts.lg
3.s2
13.43
L2.32
3 . 84
1 5 .l 8
1 5 . 4 0( 5 r )
4.73(48)
1?.s9(sr)
2.75(77',t
S.'t6(74)
6.52('t7)
t2.19
2 . 75
15.89
18.34
5. 9 2
23.84
22.39
6.81
26.r4
2 6 . 8 5 ( 74 )
8 . 3 6( 4 8 )
31.20(56)
3,62(17',t
1 . 3 6( 6 7 )
9 . 8 8( 7 7 )
(WASHINGTON)
Mean
t0
M e di a n
gOOS
ABERDEEN
57.59
w
68.I0
12.5'l
s
13.04
79.5I
81.14
Y
Percentiles
75
25
9g
M a x( v e a r )
M i n( Y e a r )
s.t9
0.31
s.16
51.76
8.47
6 4. 3 2
66.86
10.59
72 . 9 6
78.16
14.28
9 3. 6 9
83.32
t9.92
97.68
9 1 . 8 3( 7 6 ) 3 5 . 5 7( 7 7 )
s . 3 4( 6 7)
2 2 . 7 5( 7 8 )
r05.81(s6) 55.71(77)
s.2r
5.65 0.3r
25.67 9 . 1 8
r3.93
3.82
19.04
16.64
4.79
2r.75
22.38
7.l8
28.59
24.r7
7.77
32.69
29.33(55) 11.4s(44)
11.66(48) 3.30(s8)
3 4 . 0 6 ( 5 5 ) 1 7 . 0 7( s 8 )
ARIEL DAM
9242
l{
6s.79 9.22
61.48
12.67 0.33
s
12.59
74.94 s.18
v
74.L7
42.89
8.08
57.62
5 5 .r 8
9.51
64.52
67.75
1 5. 2 9
81.24
79.00
1 9 .r 3
93.42
94.18(74) 3r.74('17)
5.rs('77)
22.22(67)
I S ' 7. 9 9 ( 7 A ' , t 5 s . r S ( 4 4 )
25.98
7. 8 2
37.'17
2 9. 8 2
9.59
40.23
38.71
14.29
48.71
42.70
t6 .45
56.68
47.t2(74) 19.rs(77)
2 L . 6 5 ( 4 8 ) 5 . 5 1( 4 0 )
3 5, 5 6 ( 7 s )
6 8 . 1 3 ( 4 8)
BATTLEGROUND
0482
w
4t.37 g.I9
4 1. 3 6
s
9.35 S.3l
9.82
5 1 . 9 2 S. r 4
Y
5 1. 1 8
31.64
6.41
4t.gr
3 5 . 85
7.65
4 6" 2 9
46.15
11.47
55.97
5r.41
13.89
69.66
5 7 . 6 5 ( 74 ) r 8 . 5 7 ( ' t ' t ' )
18.43(77) 3.86(67)
6 7 . 4 7 ( 5 6 ) 3 7 . S Al ' 7 ' t ' , '
B E L L I N G H A M2 N
9564
w
26.19 g . 2 r
26.93
7.93 s.29
s
8.29
34.35 g.19
v
34.32
t9.52
5.47
2 6. 4 3
29.83
6.27
29.s7
3s.22
9.82
38.69
33.88
1r.69
43.73
3 8 . s 8 ( 7 2 1 1 6 . 5 1( 4 4 )
13.60(48) 4.36(s8)
47.92(72) 2t.87 (44)
6.82
t.25
8.76
I . 59
12.82
3.29
15.S3
t6.25
4.2r
19.96
2 s . 8 3 ( ' 74 )
s.44(?8)
2 5 . s 9 ( ' tL )
g T ' 75
ANACORTES
19.79
vi
19.51
s
v
5.9r
25.42
ARLINGTON
525'I
w
s
v
34.r2
1 1. 8 2
45.94
9668
w
s
Y
33.88 s.19
10.89 s.3r
45.54 s . 1 6
BICKLETON
rr.og
2.58
13.s8
L0.27 0 . 3 5
2.53 s.46
12,.88 g.39
9.24
rs.7r
B - l5
2 . 4 2 ( 7 7)
s.56(7s|
6 . 8 2 ( 7 7' , '
( W A S HI N G T O N)
IYlean
M e di a n
cv
Percentiles
LO
z)
tJ
9S
llax (year)
Min (year)
BLAINE
0729
w
3S.93 g.2s
3I.14
s
8.69
8.56 s.29
Y
39.83
39.49 o.r7
22.99
5.73
3s.92
2 6. 7 6
6.65
33.82
34.98
IS.S4
44.34
46.35
11.83
49.62
43.89(76) 29,58('l6l
1 6 . 6 0( 4 8 )
5 . 0 5 ( s 8)
53.93(76) 25.84(79)
987 2
BREI'IERTON
w
3 8. ' 1 9
3 8 .1 1 s . 2 9
s
6.6s
6 . 5 1 o. 4 2
Y
45.39
43.51 0.27
24.65
3.39
3s.66
29.79
3.95
3s.48
44.50
8.s8
5 3 .2 8
5 4. 4 9
L0.66
6 3 .1 4
6 4 . 5 s( 74 )
1 2 . 8 9( 7 8 )
7t.12(74)
B U C K L E YI N E
0945
t{
35.47
35.95 S.19
s
12.30
11.62 5.28
Y
4 8. 7 6
4 8 . 7 2 S .1 5
2 8. 4 7
8.61
38.97
32.28
ts.g2
43.07
41.36
14.92
55.09
46.53
1 6 . 74
58.25
4 8 . 9 4 ( 5 q ) 1 8 .r 1 ( 7 7 )
2s.46t48) 4.98(57)
63.77(48) 34.78(77)
1233
C E D A RL A K E
lr
80.63
79.74 s.18
s
22.07
21.85 0.28
Y Is2.7g ISI.26 s.16
53.11
r4.34
82.53
69.53 93.19 98.87
29.52
17.35 26.54
87.78 115.83 127.63
ts't.3s(50) 49.36(41)
3 3 . 8 2 ( 6 4 ) 9 . 1 1( 6 7 )
r31.8s(s9) 76.58(41)
I27 6
CENTRAI.IA
t{
37.59
38.97 0 . 2 r
s
8.17
7.78 s.33
v
45.77
45.87 g . r 7
24.55
4.79
35.08
33.6S
6.52
8 g. 7 r
43.94
9.32
5 3 .1 8
4 7. 9 0
13.94
54.78
53.01(56) t6.Is(7'1)
15.50(78) 4.97(52)
60.59(s6) 28.88(44)
13 5 9
CHELAN
w
8.r0
8.ar 0.28
s
2.80
1.91 o.6t
Y
10.91
Is.77 0.27
5.29
r .49
7.75
6.62
8.68
9. 4 5
3.13
I2,.55
ts.96
4 . 74
I4.9I
2 . 5 3( 7 ' 1 )
r 4 . 5 6 ( 74 )
.54(7s)
10.3s(48)
18.14(48). 4.44('19)
1385
CHESAW
4 NNk'l
w
7. 9 9
8.98 9.28
s
6.49
6.51 9.35
Y
14.39 14.39 0.24
5.27
3.68
9.83
6.30
4.9r
12.35
9.gt
7.48
15.19
ts.6s
9.18
18.Sr
r4.90 (56)
14.r2(41)
24.13(41)
1395
C H E W E L A4H S
w
1 4 .1 4
13.79 9.25
s
6.tt
5.81 0.35
v
2s.26
t9 .99 0.20
10.88
3.58
15.2I
11.75
4.32
r7 .94
16.55
7.47
22.2s
18.39
8.82
26.34
5 . 7 0( 7 7 )
2 5 . 5 9( 7 4 )
3 . 2 6( 4 3 )
r 1 . 8 2( 4 8 )
35.12(74) 11.8r(79)
1414
CHIttlACUM
w
2I.96
22.43 5.23
s
6.83
6.97 s.35
v
28.79
2 9 .l t
S.18
15.37
4.18
21.19
t9.42
4.s6
25.72
25,13
8.54
3 1. 6 3
28.52
9.83
3 6 .S 8
I . 2 5 ( 7 7)
3 3 . 6 6( s 6)
2.e3(6'7)
1 4 . e s( 4 8 )
4 s . 5 6 t 5 6 ) 1 7 . 4 3( 4 4 )
r .9I
B-16
1 9. 3 2 ( 7 7 )
2.94(4s)
23.30(44)
3 . 4 3 ( 7 7' , '
1.97(49)
6;23(49)
(WASHINGTON)
cv
Percentiles
M a x( y e a r )
Min (year )
LS
25
75
90
2 5. 4 5
8.01
3 6. 8 1
29.26
9.Ss
39.74
39.49
14.3s
51.r6
44.23
13.62
57.7r
5r .65(72',t 22.r0 (79)
20.32 (64',t 6 .20 (58',)
67.55(72) 31.54(79)
1 l . 85
t .64
r4.ss
I4.97
2.55
1 8 .3 7
z z . L t
25.86
3.1r s.53
2 2 . 3 3 9..27
3.99
2 5 . 73
29.89
3s.74(59) 7.r8(77)
0 . 9 8( 6 7 )
1 1 . 9 6( 4 8 )
3 9 . s 7( 5 9 ) 1 2 . 7 s ( 7 7 )
1586
C O L F A XI N v r
w
15.14 15.50 9.24
s
4.9L 9.36
5.3r
Y
2A.45 29.74 9.20
1r.93
3.38
15.40
12.80
4.53
L7.37
17.33
6.s7
22.79
t9.82
7.69
24.09
24.27(741 4.42(77)
11.14(41) 2.6I(69)
31.96(48) Is.28(77)
C O L V I L L EA P
I650
w
Ll.27
11.35 s.26
s
5.83
5.55 s.34
Y
17.10
15.86 s.2g
8.S1
3.57
L2.78
9.42
4.36
t4.77
t2.82
7.58
1 9 .1 5
14.S1
7.84
22.29
3 . 9 6( 7 7 )
2 s . 3 r ( 74 )
1r.42(48) 3.s9(50)
2 s . 3 9( 6 9 ) t s . 3 7 ( 7 7 )
15 6 5
CONCONULLY
w
9.67
9.45 0.3r
s
5.42
5 . 1 3 s. 4 9
Y
15.S9 14.68 s.28
6.59
2.85
I0.24
7.43
3 .5 9
11.84
11.76
6.24
r t . t 6
r3.95
8.22
29.55
15.32(74)
rs.s6(48)
2 7 . 1 1( 4 1)
4r.38
8.l7
54.19
46.79
IS.Or
58.76
65.s8
L4.32
78.67
6 8. 3 5
1 8 .g 5
86.94
82.12(76) 3s.93(77)
20.18(s9) 7.r2(52)
9 6 . s 6 ( 7 6 ) 5 0 . 2 3( 7 7 )
79.36
91.26
r17.78
SW
0.29
s.58
9.29
4.71
r.97
6.96
5.53
2.62
8.39
8.51
3.82
L2.28
9.42
5. 4 7
13.26
11.28(74)
13.4s(48)
21.65(48)
1783
C O U P E V I L L1E S
w
13.89
14.00 s.23
s
5.54
5.5r g.3t
Y
19.53
19.43 S.19
9.2L
3.47
14.75
11.75
4.60
16.48
16.61
6.76
22.1r
t7.27
8 .S 8
25.0s
8.40(44)
2r.2L(72)
11,03(48) 2.95(43)
28.49(72) 13.46(s8)
Mean
l4edian
CLEARBROOK
1484
w
34.78
33.72 g . 2 s
s
11.59
19.93 s.27
v
46.37
45.74 9 . 1 8
I5g4
CLE ELUM
w
18.99
1 9. 1 3
s
I
3.35
22.48
s.3L
I679
CONCRETE
w
55.61 53.58 s.2g
D
IZ.)U
),2.>Z
Y
68.19
64.88
9.27
0.18
1760
C O U G A R6 E
!{ 103.2r
t93.25
s
v
9.23
16.39 t6.s6 0.33
179.60 116.84 s . L 9
l'16'l
couLEE DArvlI
w
6.91
5.7L
s
3.6s
3.24
Y
I9 "5s
9.96
a.9s
r27 .77
t9.24
24.8r
ts.s6 I2.48
9 2 . 3 r L 5 4 . 9 5 1 3 5 . 1 2 L 4 8. 4 0
B-17
2.53(77)
2.22(40)
7. 7 9( 7 9 )
1 7 1 . 3 S ( 5 6 ) 4 4 . 6 ' 7( 7 ' , 7 )
28.87(41) 5.22(67)
186.43(56) 72.89(77)
r.84(77)
I.s2(70)
5.22(7'7)
(WASHINGTON)
Mean
M e di a n
CV
CUSHI'IAN
DAM
1934
l{
83.6s 0.22
85.16
9.36
s
72.et
I9.56
v
98.42 g.r9
9 7. 2 1
61.78
7.32
69.12
Percentiles
75
25
12.97
1.73
13 . 8r
rI.sg s.4L
t.62 9.52
12.77 9.37
7.32
9.37
8.83
r5.59
L4.53
2 .r t
1 5 . 88
5 7. 9 9
r0.2r
68.45
85.39 85.28
t9.42
t7.r7
94.23 rgr.2S
s.87
D A R R I N G T OR
NA N G E RS T A T I O N
1992
w
4 7. 9 9
6 7. 5 '
66.22 0.2r
s
13.7r
12.62 5.27
9.33
Y
78.03 S.I9
81.21
63.46
2Og1
9g
74.83 rg0.Ll 198.66
17.95
8.95
15.17
86.19 rr0.52 118.18
D A . L L E S P O RF
TA A A P
]968
w
s
Y
ts
r.r2
D}.VENPORT
L7.73
2S.Sr
llax(year)
Min(year)
37.9r(17)
tr2.s3(7r)
4 . 9 4( 6 7 )
2 4 . 5 3( 4 8 )
L27.64(7r) 34.12(77)
3 s . 8 2 ( 74 1
4 . 5 7 ( 4 ' 7)
3 2 . s 6( 74 )
2 . 5 3( 7 7)
s . 1 6 ( 7s )
5 . 2 L ( ' t 7)
97.6L(74) 38.10(77)
8 . 3 s ( s 7)
2r.66 (72)
l.ls.Ls(74) 5s.91(77)
2 . 6 t ( ' t 7)
2.27(49)
I .s3 (77',)
rr.90
9.75
3.22
r3.68
t2.93
5.67
1 7. 6 9
14.29
6 . 65
20.16
r 7 . 4 4 ( 74 )
14.95(48)
2 8. 2 4 ( 4 8 )
LA.49
2.73
14.33
12.Sr
3.27
16.s5
r6.35
6.s4
2r.73
1 8 . 74
7.65
23.65
5 . 2 4 ( 7 7)
2 S. 3 6 ( 74 )
2"3r(53)
12.ss\4r)
28.20(48') 11.16(77)
10.85 0.30
72.r8 g.2r
43.71
7.57
5 5. 2 3
52.s9
9.49
63.46
74.98
13.71
8s.17
85.54
15.53
9 8 .t 0
ra2.63(76) 3s.83(73)
5.86(67)
2s.8I(72)
1 r 5 . 8 8( 7 6 ) 4 s . 4 6( 7 3 )
ELLENSBURG
2505
w
6.7s
6.56 9.32
s
2.22
1.86 g.5g
v
8.92
8.79 0.28
3.82
r.23
5. 4 4
5.3A
r.63
7.5s
7.95
2.6r
19.35
9.55
3.49
L2.68
11.66(74)
7.14(48)
1 3 . 6 5( 4 8)
253I
ELY,A
w
55.94
55.65 g.19
s
Is.e9 . 2 1 s.32
Y
65.95
64.5'7 g . r 7
4s.37
6.6s
5 s. 7 " 1
49.41
7.99
58.61
63.82
11.19
73.68
75.52
15.6S
I3.98
7 6 . 7 9 ( 74 ) 3 s , 4 7 ( 7 7 ' , )
17.43(68) 4.s8(67)
8 6 . 6 8 ( 7 6) 4 6 . 4 4 ( 7 7)
19.r4
5.59
28.23
22.49
6.54
30.7r
3 S. 3 3
1S.61
3 7. 8 2
34.56
13.01
45.31
3 7 . 8 2 ( 4 8 ' ) 1 5 . 3 3( 7 7 )
r?.s5(48) 4.14(s8)
55"38(48) 22.8t('t9)
w
s
Y
rr.29
4.51
15.93
11.67 s.25
4.I2 g.48
16.15 0.23
2O3A DAYTON
I WSW
!{
14.33
IA.32 0.23
s
4.87
4.30 0.4r
Y
1 9. 1 6
1 9. 6 9 S . 2 g
2157
DIAtsLO DAI|I
w
62.8>
6I.35 0.24
s
v
zo t)
w
s
Y
rr.67
74.52
r-VlxEl
26.66
8.9.
3 5 .5 7
7.72
2.6t
t
27.38 s.2t
8.65 s.35
3 5 .S I s . t 9
B - l8
1.58(77)
s.75(7A',)
4 . 2 s ( 73 ' )
(wASHTNGTON)
Percentiles
llean
29T4
w
s
v
cv
M e dI a n
FORKS 1 E
94.8s s.2g
9 7. 7 8
18.42 L7.75 9.28
Lr6.2s 113.23 s.t7
Tg
75
25
9s
74.35 85.96 rsg.6S 126.5r
13.95 14.99 21.9r 25.18
9r.97 tss.72 t3S.br t42.92
Hax(year)
Min(year)
143.26(76) 61.87(79)
9 . 7 4( s 8 )
3r.03(48)
1 6 1 . 5 4( 7 6 ) 8 s . 5 7 ( 4 9 )
GOLDENDALE
3222
t{
14.45
14.59
2.58
s
2.72
16.9s
Y
17.31
s.29
s.39
0.24
9.52
1. 6 8
11.36
12.11
2.93
14.63
17.18
3.38
2s.34
L9.72
3. 9r
22.7s
23.36(s1)
5.89(48)
26.19(s1)
GRAPEVIEW3
3284
l{
44.11
43.95
s
7.77
6.89
Y
51.88 5r.82
SW
9.21
g.36
0.L8
3s.79
4.73
38.98
38.8s
6.s6
45.87
51.54
8.97
59.32
56.73
11.73
64.55
57.84(50) 2s.48(771
3.72167)
1s.81(48)
6 6 . 7 9( 7 2 ) 3 3 . s 6 ( 7 9 )
45.22 0.2r
r0.63 s.31
56.74 s.L9
3 3. 2 6
8.25
43.23
3 9. L s
9.46
59.89
5 3 . 63
L4.93
68.92
5 7. 9 7
t7.67
72.t6
6 5 . 0 2 ( 5 9 ) 2 5 . 4 1 ( 7 ' tI
2s.74(48',) 3.57(67)
8s.30(59) 39.sr(77',|
H A R R I N G T O5N S
3592
r{
8.89 9.2-1
8.88
s
3.I9 s.63
3.?9
Y
12.68
12.49 9.27
6.r3
2.03
8.82
7.s8
2.65
10.53
I5.67
4.98
L4.20
r1 .66
5.94
1 5 . 8I
16.45(74)
15.5s(48)
27.54(48)
2.58(77],
I.L2(7s)
7.32(49)
HARTLINE
3529
w
7.46 0.31
7.35
s
3.47
3.r2 S.58
Y
rs.82
19"42 9.29
4.74
I .81
7.45
6.59
2.48
8.A7
8.88
3.76
L2.45
9.89
4 . 74
r3.29
1 4 . 4 7( 7 4 1
12.66(48)
21.14(48)
1 . 6 8( 7 7 )
s,8rl7s)
5.s4('7'7)
H A T T O N9 E S E
3546
v{
7.43
7. 6 3 0 . 3 9
s
2.72
2.4r 5.44
Y
19.15
9.7r 9.24
5.s3
1.63
7.42
5.54
r .96
8.46
8.98
3.77
1r.53
Ls.76
3.95
L3.24
13.03(74)
7.56(48)
18.72(48)
2.SI(77)
5.76(7s)
6.34(77)
I{AUCONDA
IRENE MOUNTAIN
3975
w
1.a7
7.16 s.26
5.l8
s
7.97
3.96
6.81 5.39
14.56 s.25
9.65
Y
14.54
5.96
4 . 7A
12.16
8. 6 4
8.19
1 6 . 72
19.53
Lg.s7
18.58
r1.83(58)
1s.21(41)
24.56(4r)
2.78(77)
3.43(7s)
7.89(7?)
5 . 85
r.94
8.30
9.gg
3 . 82
rt.7g
11"18
4.27
13.29
1 4 . 1 8( 7 4 )
6.63(48)
17.96(48)
1 . 8 6( 7 7 )
r.03(70)'
5.r7(77',t
3357
w
s
t
GREENWATER
45.69
12.s2
57.7t
4g'l'l
KAHLOTUS
5
l{
7.65
?.t9
s
2.89
2.58
v
ts.46
19.65
SSW
S.3S
5.42
9.24
5.25
1.51
7.29
B-19
2.63(77)
0.52(7s',)
7.82(77)
(wASHTNGTON)
Mean
lledian
CV
l0
4084
K A L A I ' I AF A L L S H A T C H E R Y
w
38.45
52.17 5s.5t 0.22
s
1r.60
1r.13 s.34
7.29
y
6 3. 7 7
6 0. 5 3 s . l 9
5I.41
4154
KENNEWICK
Percentiles
75
25
9g
Max(year)
Min(year)
4 4 . 7s
8.46
15.27
58.64
13.66
7L.37
79.02
l8 .19
81.78
8 3 . 5 9( 7 4 ) 2 4 . 5 3 ( 7 7 )
19.8s(77) s.33(67)
9 4 . 5 8 ( 7 4 ) 4 2 . s 4( 4 4 )
4.r3
1.33
6.L0
6.94
2.59
8.95
8.58
3.58
r9.65
11.57(74)
5.93(481
1 s . 5 0( 4 8 )
1.89(77)
S.so(49)
3 . 9 2( 6 4 )
9.37
5.52
s.3g
3. 4 s
t.s5
5. 4 5
42OT KID VALLEY
w
4 ' 7. I 2
46.'l'1 g . 2 g
s
12.44 11.98 9.32
Y
5 9 .5 7
58.56 0.r6
34.51
7.38
4 7. 9 8
43.s9
9.67
52.68
53.99
15.91
6 5 . 74
59.45
18.28
73.43
68.31(s6) 25.26(77)
6.4s(70)
2 5 . 7 7( 7 7 )
8S.4s(s6) 4r.58(79)
7.26
2.12
9.66
8.29
2.58
12.24
1r.62
4.29
15.S8
13.3r
5.55
L7.22
r7.32(74)
8.88(48)
22.52(48)
4394
LAKECLE ELUM
w
32.09
32.36 9.25
s
4.4A
4.34 0.38
Y
35.50 35.36 5.23
21"31
2. 6 7
2 5. 4 8
24.42
3.24
28.04
37.77
5.31
42.47
41.78
6.89
45 . 9 1
5 3 . 2 7( 7 2 )
IS.3s(48)
5 8 . 8 7 ( 72 ' )
4406
LAKEKACHESS
t{
44.18 45.65 0.24
s
7. 2 0
5.7s s.35
Y
51.38 51.55 9.22
29.52
4.7s
50.12
35.99
5.65
42.27
51.18
8.34
5 9. 8 9
57.86
9.99
65.82
68.58(72) 23.s3(77)
r . 6 4( 6 7 )
r s . 2 1( 4 8 )
77.8r(72) 3s.6s(79)
4AI4
LAKEKEECHELUS
w
56.97
58.61 s.22
s
9.53
9.r2 s.32
Y
66.50 66.53 S.2S
3 9. 6 7
5.18
49.53
46.62
?. 3 s
53.41
6 4. 6 3
r0.93
78.26
74 . 5 2
13.96
83.79
8s.78(72) 33.24(41)
2.53(6't)
17.66(59)
9 9 . 9 5 ( 7 2 1 4 3 . 9 s( 7 7 )
4446
LAKEWENATCHEE
w
35.37
3 ' 1. 2 4 9 . 2 4
s
4.78
4.44 0.49
4Q,.I4 42.t'7 0.22
"Y
2 3. 4 9
2.56
27.76
27.41
3.45
31.68
4I.37
6.s3
46.95
46.89
6.90
5S.Ar
s3.15(56) 18.97(77)
r.7r(75)
1r.84(48)
58.57(s6) 25.68(77)
4486
LANDSBURG
w
43.4A 43.38 g.18
s
r 3.l0
1 2 . 5 2 g. 3 a
Y
55.50
56.73 s.16
32.98
8.93
44.87
3 7. 4 5
rs.52
48.99
50.38
16.s6
64.36
54.42
18.66
68.98
s5.99(74) 23.42('.l't)
6.sr (67)
23.0r(64)
74.L9(48) 39.s3(77)
kll
q
Y
qJSb
w
s
Y
5.69
2. 0 5
7.74
LA
t0.10
3.61
13.73
5.99
1.73
'1
.35
LKUbSE
Ig.'77 0.25
3 . 1 7 0. 4 3
13.68 9.23
B-20
3.52(77)
1.93(7S)
7.rt(77)
15.46(77)
0.73(67)
2 2 . 7r ( 7 ' 7)
(WASHINGTON)
Mean
LS
lled i an
LAURIER
4549
w
11.6S a.23
1 '11 . 9 4
7. 1 7 5 . 3 6
.44
s
19.42 S.2s
Y
19.38
Percentiles
75
25
90
M a x( y e a r )
Min (Year)
9.gr
4.55
r3.94
9.81
5.53
r6.84
r3.79
8.87
22.49
15.22
19.11
23.75
18.s9(74) 5.39(77)
16.96(41) 2.3s(6't)
39.82(4L) 1r.94(77)
20.4r s.3g
2.90 9.56
23.r5 0.27
13.33
r.52
L6.75
r7.54
2.I7
29.34
23.53
4.s3
2 7. 5 3
29.25
4.8s
34.39
7.86(77)
37.62(56)
11.26(48) 5.37(75)
42.5r(56) t2.38(77)
LIND 3 NE
4679
6.65 s.3s
w
6.93
2.68 9.58
s
2.99
9.31 s.3r
Y
9.91
a.69
1.64
7.18
5.38
r .91
8.92
8.s9
3.34
r0.85
I5.02
4.30
12.56
1 1 . 8 3( 4 1 )
11.39(48)
22.32(48)
1 . 9 3( 7 7 )
1.13(49)
5.96(77)
LONGVIEW
4769
l{
36.94 g . 2 r
36. 59
8.36 9.32
s
8.94
4 5 . 3 5 0. 1 7
v
45.53
2 5. ' l 3
5.75
34.85
33.17
7.98
41.09
4r.73
19.26
5r.08
46.92
14.96
55.95
4 9 . 6 7 ( 74 l
r s . 6 9( 7 8 )
s9.78(s6)
I4.54(771
4 . 3 1( 5 7 )
29.9r(77',)
M A N S FEI L D
4 9 ' 7I
7.79
?.68 s.29
w
2.85 0.62
s
3.43
11.13 1I.05 0.28
Y
4.48
r . 74
7.72
6.67
2.25
9.24
9.s9
4.28
L2.27
r0.07
5.0s
14.65
t 3 . 8 2 ( 74 1
13.9s(48)
2 2 . 8 4( 4 8 )
2 . 7 A ( 7 ' t)
0.46('ts)
5 . s 5( 7 9 \
MAZAI'IA
6 SE
5128
w
L4.7r s.28
15.25
3.79 9.52
s
A.rs
18.85 9.26
19.4?
Y
rs.g5
2.r4
13.58
13.29
3.s5
16.17
17.29
4.33
21.49
2r.7L
6.18
27.52
2 s . 2 t ( 72 )
r4.r6(48)
33.25(72)
5. 45(77',)
I.6r(75)
9.66(77)
I , I C MLIL I N R E S E R V O I R
5224
22.95
l{
30.67 g.2r
3I.34
5.23
I "67 0.3r
s
8.75
35.58
4s.48 S.L7
49.09
v
26.88
6.57
34.33
36.17 4r.s8
11.S9 12.33
46.14 48.78
4 2 . 7 9( ? 4 )
14.32(48)
5 3 . r 5( 7 2 )
I4.31{77)
3.44(52',t
2 5 . r 1( 4 4 )
MINERAL
5425
w
7r.43
79.35
1 3 .1 7
12.93
s
84.36
83.29
Y
s.28
0.3r
s.24
45.13
7.93
58.61
5 9 .s 9
9.95
79.79
81.52 95.56
r5.97 18.9s
95 . 3 4 r 9 8 . 7 7
MONROE
5525
9!l 36 .75
36.88
g.I7
2 8. 4 2
7.24
3 9 .r 6
32.4t
8.71
41.87
4r.37
r2.89
53.65
4572
w
s
v
s
y
3 S
LEAVENWORTH
2r.29
3. 2 8
24.57
1r.07
a7.82
1 0 . 7 r g. 3 r
46.86 s.l4
B-21
44.2r
r5.95
57.85
r16.39(74) 22.85(79',)
4.77(7s)
2r.26159)
L 3 2 . 4 9 ( 7 4 ) 3 1 . 4 1( 7 9 )
51.86(74) 22.35('t7)
4.27(67)
t8.62(71)
53.34(48) 36.4't(79)
(WASHINGTON)
Percentiles
Mean
56 1 3
HI
e
Y
M e di a n
CV
M O S E SL A K E 3 E
5.62 s.32
5.78
2.27 9.49
2.45
8.23
8.20 g.3S
15
9g
3.65
L.05
s. 39
4.5s
r.67
6 .r 8
6.82
3.22
9. 6 3
7. 3 s
3.s3
rr "45
1S.66(41)
6.93(48)
14.S9(48)
33.30
3.35
39.28
48.29
5.75
s3.93
55.53
7.80
50.58
6 6 . 2 9( 5 6 ) t 2 . 4 5 ( 7 7 )
10.64(48) t.24(79)
69.18(s6) 25.47(17)
3.29
9.94
5.22
4.29
1.54
6.25
6.72
2.95
9.16
8.19
3.82
tr.2s
11.42(s3)
5.42(48)
r2 .92 (53',)
29.13
9.77
45.38
33.41
12.45
46.81
44.66
17.6s
61.S3
49.6s
25.79
6 7. L 4
53.I4(74) 24.s5(42)
5 . 8 4( 6 7 )
24.s5(68)
69.A8(74) 39.69(s2)
63.26
11.?7
77.25
7 2 , 8 9 9 8 . 5 2 r g 7. 3 7
1 3 . 2 6 r 7. 8 2 2 2 . 5 r
86.93 L12.26 r 25.35
131.44(76) 42.s9(79)
39.33(78) 8.32(67)
L48.04(76) 55.82(79)
I.,IOUNTADAMS RANGER STATION
5659
41.35
42.76 9.28
24.92
4. 8 4
4 . 76 S. 4 4
2.23
46.18
4 7. 2 2 9 . 2 4
3s.34
5688
M O X E EC I T Y
5.68
5.60
2.12
2.33
8.s6
7.84
Ig E
9.37
9.48
0.29
DAM
5 7 9 4 M U DM O U N T A I N
38.98 38.13 0.t9
ls.s9
14.55 0.26
54.06
52.42 9.15
lll
S
58sr
lt
S
Y
N E A HB A Y 1 E
84.76
80.90 s.2r
I6.I7
1 6 . 0 3 g. 2 6
r00.93
99.89 g. 1 9
5 83 2 N E S P E L E 2M S
w
9.00
8.52 5.29
Y
4. 2 8
r 3.28
3 .5 4 g. 5 9
12.92 s.35
NE W H A L E M
5840
W
65.21
53.51
D
Y
S
Y
c
Y
7.4s
2.87
t s . 74
lg.7 r
4.94
r5.49
12.66
6.31
1 8. 7 1
75.68
8 6" 2 s
19.s3
Lss.47
15.65(74)
15.37(48)
27.94(48)
I.2s(77)
S . 4 0( 7 s )
3 . 7 4 ( 79 )
2.26(77)
t,s2(49l,
7.22(77)
4 1 . 3 2( 4 4 \
9 2 . 5 7 ( 74 )
22.32(591 6.12(75)
1 1 S . 1 3( 5 9 ) 5 5 . 7 7( 7 3 )
s.2g
s.27
0.18
46.44
9.69
59.r2
s6.3r
1r.08
6 7. 7 r
88.98
NEWPORT
20.28
29.ts
7.54
7.26
2 7. 8 2
28.19
g.2t
s.29
s.t6
14.38
5.59
20.r8
L8.s4
6.32
25.64
22.64
8.46
35.92
rs.26
3 2 . 7r
26.08
3r.04(741 8.67(77',t
r3.s3(48) 3.83(s8)
3 7. 6 ' 7( 74 ) 1 6 . 3 8( 7 ?)
s.2g
9.35
s.17
9.5s
4.26
15.32
r0.91
5.21
17.49
t4.18
8.99
23.58
15.83
10.38
24.34
r8.67(69) 6.72(77l
r5.35(41) 2.8s(67)
2 9 . 5 8 ( 4 1 )1 2 . 3 r ( 7 3 )
5946
w
6.19
2.38
9.12
r.92(77)
5.74(7sl
4.29(73)
13.12
76.5A
13.54
78.75
5844
w
Min (Year)
25
li
w
M a x( y e a r )
Ig
NORTHPORT
12.69
I 2.61
't.3'7
7.I3
20.06
r9.73
B-22
r5.6s
(!'TASHINGTON)
Percent i les
?5
25
9s
M a x( v e a r )
Min (Year)
cv
IO
0.21
s.57
9.28
4.88
1.61
7.r5
5.?8
1.95
8.15
8.53
3.7s
12.t4
9.7't
4.75
13 . 3 7
I0.98(74)
lo.6r (48)
19.29(48)
2.23(77)
s.62(7sl
s.13(49)
oLGA 2 SE
6996
22.05 9.20
w
22.5r
6.52 s.26
s
6.58
28.99 g.r8
v
29.ts
16.97
4.56
22.s8
19.26
5.r2
25.51
2 6. 1 r
7.58
32.38
2 8. 3 1
8.72
36.49
3r.52(72l1 2 . 1 4( 4 8 )
38.76(64)
14.23(79',)
4 . 3 9( 6 7 )
19"sJ('te)
O L Y I ' I P I At t l s OA P
6114
4r.23 9.25
w
4t .39
6.83 9.38
7.75
s
48.38 5.22
49.14
Y
27.45
4.92
35.90
35.35
5.68
4I.47
48.14
I .86
s 8. s 4
s6.49
13.34
62.89
6 0 . 5 7( 7 2 1 t 7 . 9 7 ( 7 7 )
3.r3(67)
r 4 . 9 9( ? 8 )
69.93(72]. 27.st(44)
5.49
8.42
6.33
2.49
9.42
9.93
a. 5 2
L4.gg
11.49
6. 6 1
16.67
16.r3(74)
12.9s(48)
23.34(41)
53.84
13.5?
74.53
59.47
1 7. 6 9
7 9. 8 7
P L E A S A N TV I E W
6553
0.2?
w
9.12
9,4'7
3.23 5.47
s
3.44
13.94 9.22
12.91
Y
6.18
I .84
9.75
7.'t7
2.58
Ir.s8
11.12
4.18
r4.75
13.14
6.11
15.79
1 6 . 1 9 ( 7 4)
8.28(48)
2 L . 2 9( 4 8 )
2 . 5 r ( 7 7)
r.47(63)
6.72(77)
66TO POMEROY
w
11.96 5.24
II.58
4.14 5.39
s
4. 5 6
16.18 S.2s
Y
16.13
8.r4
2.66
11.9s
9.65
3.42
13.48
13.21
5.34
18.28
15.10
6.6r
19.66
r7.48(48)
r 1 . 3 9( 4 1 )
2 4 . 4 9( 4 8 )
4.26(77)
2 . 3 8( 6 7 )
rs.2a(77')
P O R TA N G E L E S
6624
2s.65 0.23
w
29.44
s
4.2r
4.00 0.31
25.11 S.2r
v
2a.55
14.61
2.59
17.88
16.64
3.26
29.83
24.23
5.56
28.36
26.65
6.s4
32.55
29.84(54)
7 . 2 9( 4 8 )
3 4 . 5 1( s 4 )
10.86(44)
2 . 3 6( 7 3 )
r 4 . 9 9( 4 4 )
P O R TT O W N S E N D
66'78
w
13.r9 0.21
13.52
5.64 5.32
s
5.65
19.36 0.L7
Y
1 9. 1 8
I9.ST
3.44
15.31
11.96
4.24
r6.63
15.69
6.63
2r.45
r '?t . 1 3
.4s
23.14
'7.3r(77)
19.95(?1)
(
4
8
)
2.66(52)
r1.9q
2 7 . 7 0 ( 4 8 ) 1 2 . ' 76 ( 7 3 )
Mean
Median
oDESSA
6939
7.54
w
1.26
2.84
s
3.98
I0.4r
19.34
Y
o M A X2 N W
5123
8.65 A.32
w
8.47
3.43 0.56
s
3.98
12.27 0.39
Y
12.44
6295
w
s
v
z. zz
PALMER 3 ESE
7s.63
21.56
92.r9
'1r.93 S.2S
20.8I 5.29
8 8. 5 9 S. r 7
B-23
89.58
83.12
29.2L
25.96
154.65 114.19
2 . 4 7( 7 7 )
t.0s('ts)
6.9s(79)
9 6 . 2 5 ( 6 r ) 3 6 . 6 7( 7 7 1
38.4?(59) 9.49(67)
131.S5(s9) 63.6s(77)
(WASHINGTON)
t'lean
MeCian
CV
Ig
Percentlles
75
25
9g
|tax(year)
I'1in(year)
P R O S S E 4R N E
6768
5.87 9.35
w
5.86
1.92 9.46
s
2.29
8.s2 0.28
8.15
Y
3.2r
r.20
5.58
4.54
r.60
6.64
5.96
3.11
9.26
8.62
3 . 89
r1.61
10.62(s8)
4.59(41)
12.76(4r)
P U L L M A N2 N W
6789
t{
15.A0 9.25
15.39
4.93 9.32
s
5.48
2s.83 S.2r
Y
20.87
t0.42
3.57
15.31
12.54
4.40
17.86
r7.96
6.23
23.53
2r.tg
8.7I
2 7. 6 9
23.2s(74) 5.r5(77)
2.94(69)
rs.s8(4r)
3 1 . 0 s ( 5 9 ) r 3 . 1 9( 7 7 )
T TATION
P U Y A L L U P2 W E X P E R I M E N S
6893
23.29 28.15
w
31.29 0.2r
32.I5
4.81
5.82
7. 7 8 5 . 3 3
7. 9 2
s
35.36
30.82
4A.6r g.l7
Y
4 A. 0 ' t
36.61
9.38
a5.92
42.46
11.33
48.43
4 3 . 5 0( s 6 )
r4.8s(48)
5r.49(72)
6846
Q U T L C E N2E S W
w
44.53 5.23
45.22
8.71 9.35
s
8.99
54.28 5.20
v
54.22
3r.26
5.31
38.12
38.96
5.65
48.62
s1.56
10.91
6r.5s
59.64
r3.45
69.26
6 6 . 3 7( 74 ) 1 8 . 4 1( 7 7 )
3.73(67)
1?.93({8)
76.8s(56) 3L.74(77)
6880
Q U r t i C YI S
w
5.90 s.35
5.72
1.96 0.5'7
s
2.26
7. 8 7 g . 3 s
7.98
Y.
3. 5 1
0.99
5.57
4.A6
6.94
6.65
2.68
9.82
8.23
3.69
1t.14
11.87(74)
7 . 1 6( 4 8 )
13.8s(48)
RAIr*iER-OHANAPECOSH
6896
44.92
w
6 5 . 8 7 6 7. 2 2 0 . 2 3
6.79
L0.48 0.32
s
1I.07
55.44
76.94 76.86 S.L9
v
57.54
8.82
66.8't
73.34
r2.85
8 7. 2 I
83.78
16.59
96.36
L s s. 2 3 ( 72 )
1 8 .s 3 ( 7 8 )
1 r 3 . 3 8( 7 2 )
3 3. 4 5 ( 7 7)
4 . 5 9( 6 7 )
49.sr(731
RANDLE 1 E
6999
w
49.38
4 9. 2 9
s
I0 .27
1 0 . 74
65.82
v
69.03
9.22
0.31
g.18
35.52
6.72
46.16
43.50
8.38
5t.24
5 7 .1 9
13.49
6 7. 9 8
62.59
15.57
72.54
6 9 . 8 7( 7 2 )
r7.r2(4r)
83.5s(72)
2 5 . 4 7( 7 7 )
4.52(67)
37.5s(77)
REPUBLIC
6 9 74
9i
9.91
9.51
s
5.76
6.24
15.61
v
16.14
0.27
g. 4 r
s.20
7.s4
3 .3 8
t2"98
8.32
4.63
13.96
L5.98
7.34
r8.75
14.rg
9.17
2s.25
A . 2 9 ( 7 7)
1 6. 7 7 ( 74 )
2 . : 1 7( 6 7)
1 5. 2 1 ( 4 1 )
23.96(41) tS.rs(77)
r7.15
2.85
18.93
25.5s
4.96
29.43
30.28
4.79
34.19
3s.35(56)
9.3s(48)
39.53(72)
1938
w
s
Y
RIMROCK (TIETON DAM)
2 r. 6 1
3.51
25.r2
2r.72 s,3g
3.3'1 5.40
25.99 5.28
13.29
2.rr
16.78
I . J /
B- 24
1.58(77)
0.65(70)
4.27(79)
14.56(77)
3.52(52)
27.18(77)
r.22(77','
S . 7 1( 6 3 )
3.s9(79)
6.s2177)
9.13(7s)
9.53(77)
(t{ASHTNGTON)
Mean
M e di a n
7 559
RITZVILLE 1
t.J
8.41
8.43
s
3.3S
2.95
Y
1 1. 7 1
11.56
CV
ssE
s.25
s.59
Tg
Percentiles
25
75
90
l i l a x( y e a r )
Min (year)
9.27
5.93
1.69
7.66
7.s8
2.26
rs.34
t0.12
3.61
12.98
19.83
4.64
14.73
I3.49 (74)
13.91(48)
2 3 . 8 5( 4 8 )
2.45(77',)
r.r3(49)
5 . 7 8 ( 7 7)
s.24
s.38
r7.72 9.23
9.59
3.55
12.93
Is.9s
3.76
16.gs
14.58
6.s5
2s.98
16.48
7.44
22.54
L9.79(74)
r 2 . 3 4 ( 4 8)
3r.72(48',)
4.66(77)
2 . 5 0( 6 6 )
9.96 (73)
7473
S E A T T L E - T A C O MW
AS OA P
l{
31.I3
31.25 9.22
22.55
s
7.65
6.82 9.36
4.s6
y
3 8. 1 7
3 8. 3 9 0 . I 9
28.51
27.22
5.16
33.55
35.46
g.s6
44.03
4 s. 4 2
1A.48
48.54
42.3slsr)
t4.15(48)
5 0 . 8 3 ( 72 )
7 4 ' 7 8 S E A T T L E - U N I V .O F T { A S H I N G T O N
w
28.62
29.29 g.t9
20.63
25.95
s
6.93
6.08 9.36
4.44
5.90
Y
35.56
35.73 g.I7
27.88
3s.93
33.6s
8.69
49.56
35.08
r0.60
43.29
36.59(s6) L3.25(77)
13.78(48) 3.16(58)
4 7 . 5 7 ( 4 8 ) 2 3 . 6 0( 7 9 )
75 0 7
s E D R oW O O L E Y
w
3 4 . 3 4 33.77 0.2I
s
11.35 11.65 5.2'7
Y
45.7I
44.98 s.78
23.37
7.46
35.6s
29.85
9.43
38.85
39.69
13.50
52.18
43.37
t5.57
56.97
5r.39(59) 2r.99('17)
r 8 . 9 8( 6 4 )
6.53(s8)
68.00(59'.,3r.18(79)
75 3 8
SEQUIM
w
11.81 12.19 o.2I
s
4.16
3.9r 9.35
Y
15.97
16.s8 g. I 8
7.92
2.52
12.31
ts.6r
3.29
13.86
13.53
5.55
I7.41
15.92
5.58
19.52
1 6 l ' 2 9( 5 7 )
9 . 3 6( 4 8 )
23.42(48)
7584
SHELTON
w
55.74
54.57 0.22
s
8.5s
7.82 s.34
Y
64.24
63.?5 g.2s
3 8. s s
5 . 85
45.29
46.97
6.69
55.25
6s.65
9.59
74 . 3 I
7r.52
r4.s4
8r.22
7 6 . 9 8 ( s 6 ) 2 6. 4 0 ( 7 1 i ' , )
1 s . 7 3( 4 8 ) a . 1 4 ( 6 7 )
85.8s(72) 4r.75(77)
7773
S N O Q U A L M IFEA L L S
l{
48.34
46.44 0 . 2 I
s
12.53
tr.74 s.3s
Y
60.86
5 9 . 5 3 s .t 8
3 4. 9 9
8.66
46.4s
4 2 . 73
9.36
53.39
5 5 . 91
15.4s
7 S. 8 4
6 t .r s
r7.15
76.31
66.95(74) 2s.37(77)
2t .72 (48)
4 .76 (67',)
82.36(48) 39.5s(77',t
7938
S P O K A NW
E S OA P
t{
12 . 1 6
12.29 o.27
s
4.84
4.32 5.38
Y
16.99
16.59 9.22
8.31
2.87
12.23
9.49
3.80
t5. s1
14.85
5.48
1 9 .5 1
15.99
7.22
2 g. 4 9
r8.45(74)
t s . 9 0( 4 8 )
28.78(48)
7 I8O
ROSALIA
w
12.79
12.85
s
5.23
4.93
v
18.a2
B-25
12.35(77)
3 . 3 9( 6 7 )
2 3 . 1 6 ( ' 7 7)
6 . 5 8( 4 4 )
2.s6(57)
9 . 1 1( 7 3 )
3.96(77)
2 . t 9 ( 74 )
I0.25(73't
(WASHINGTON)
Mean
7956
w
s
Y
cv
SPRAGUE
rs.97
4.s2
14.99
7987
w
s
v
ltledi an
11.08 4.25
3 . 5 9 o. 4 L
14.83 9.22
SPRUCE
r07.9I r55.62
19.79
20.3A
I28.25 r27.35
s.t9
0.26
g.16
S T A R T U P1 E
8034
w
4 8 .5 6 g . 1 8
4 8. 8 6
16.40 0.28
s
16.21
v
65.5'7 62.55 s . 1 6
8959
|{
s
v
Tg
8.r0
2.52
rL.o7
29.8r s.24
3.78 g.A4
3 3 . 7 8 s. 2 3
9.03
2.9s
13.52
12.89
4.84
16.55
9g
L4.37
5.55
19.23
M a x( y e a r )
17.95(74)
L s . 2 6( 4 8 '
24.8s(48)
t!in (Year)
3.24(77)
r.82(49)
7.40(77)
92.16 123.13 135.43
8r.56
2 8. 8 9
1 3 . 5 7 1 6 . 3 5 2 2 . 74
L S r . g r 1 r 2 . 93 1 4 5 . 3 8 l 5 r . 5 6
r52.ts(76) 67.X3(77)
3 2 . 9 3( 7 8 ) 1 5 . 4 6 ( 6 7 )
1 7 2 . 1 2 ( 7 6 ) 8 9 . 8 3( 4 4 )
39.08
9.92
53.34
42.66
13.44
57.39
55.37
19.56
72.rs
6r.48
22.85
86.25
6 s . 7 4 ( 74 ) 2 9. 8 2 ( 7 7)
6 . s s ( 6 1)
2 5. 5 7 ( 4 8 )
87.8s(48) 47.73(73)
2r.66
2.67
25.23
24.84
2.9'1
29.67
34.95
5.42
39.88
38.93
6.32
45.98
s s . 7 4( 5 1 )
1 9 . 6 3( 4 8 )
56.42(51)
] 3 . 9 9( 7 7 )
1 . 8 0( 6 7 )
19.26(77',)
r5.8s(74)
4 . 6 s( 4 8 )
16.72(74,
L"2r(77)
0 . 2 8( 7 0 )
3.86(79)
STEHEKIN 4 NW
3 0 .1 9
4.34
3 4. 5 2
Percentiles
75
25
SUNNYSIDE
8291
4 . 4 4 s. 4 8
w
4.96
1.5s 0.54
s
1.97
y
6.89 s.35
6.94
2.73
s.75
4.33
3.55
t.2s
5.18
5.93
2. 6 4
7.63
7.95
3.58
9.97
HALL
g.2r
0.49
0.r8
2 1. 1 6
3.94
2 8 .1 5
26.56
4.7r
33.22
34.14
8.17
49.88
3 8. 7 4
19.61
46.29
4 2 . 8 4( 5 6 ) 1 3 . 2 5 ( ' 1 ' 1 )
14.8s(48) 2.22(521
5 0. 2 t ( 4 8 ) 2 r . 6 6 ( 5 2 )
TEKOA
8348
15.42 s.22
w
1 4. 8 4
s
6.23
5 . 6 7 g. 3 7
g.2l
y
21.97
2I.2I
11.56
3. 9 1
1 5. 8 9
12.49
4.61
]8. 57
16.65
7.58
2 3 . 13
18.29
8.85
25.31
4 . 5 ' t( 7 7 )
22.rr(48)
2.56(741
t4.s7 (48)
36.18(48) ls.20('t7t
25.47
4.42
33.96
28.51
5.81
35.41
37.33
9.34
45.95
4r.s2
11.12
48.sr
1 2 . 8 6( 7 7|
4 9 . 8 5 ( 7 4)
2.52(67)
1s.0s(68)
56.44(74', 25.72('17)
8.07
2.43
r2.11
to.t2
3.38
13.89
13.94
5.53
18.90
14.85
6.2"1
19.64
5.94(77]t7.42(7Al
1.64(74)
9.63(4r)
25.02(48) I1.r6(77)
CITY
TACOMA
8286
w
35.69
30.09
6.53
s
6.80
36.90
Y
36.89
V A N C O U V E4R N N E
8 7 73
w
32.84 s.2r
32.89
Y
7. 5 2
4 0. 4 1
7. s 2 0 . 3 4
39.93 g.17
W A L L AW A L L AW S OC I
893I
w
11.59 11.7r 9.24
3.88 5.39
s
4.34
15.S3 15.84 S.18
Y
B-26
(WASHINGTON)
Percentiles
75
25
90
I i l a x( y e a r )
tlin (year )
cv
Tg
s.38
s.53
s.32
2.93
I .81
4.9s
3 . 9t
r.26
5. 7 1
6.5s
2.56
8.72
7. 9 2
3.35
11.14
rL.0z(74)
s.10(48t
1 2 . 6 9( 5 5 )
1.0s(72)
s.26(7s)
3.23(7g',)
5.rs
6.64
2.32
9.94
8.86
4.33
L3.97
ts.69
5.09
r4.58
1 3 . 6 6( 7 4 )
13.87(48)
2 3 . 8 4( 4 8 )
r.73(77)
s.28('ts)
5 . 2 7( 7 7 ' , t
14.57
11.95
4.2'l
I7.24
16.67
6.79
2r.95
19.23
8.16
25.86
2 3 . 5 s ( 1 A ' , , 5 . r 5 ( 7 7)
2.4r(67)
1 2 . 8 s( 4 8 )
2 8 . 8 r( 4 8 ) I s . 5 S ( 7 7 )
WENATCHEE
9 g ' I4
w
6.81 9.28
6.58
2.04 s.70
s
2.33
8.67 9.28
Y
8.91
4.t?
s.73
5.85
5.42
1.43
7.s3
7.46
3.t2
9.82
8.98
4.44
12.40
r0 .98(74')
9.ss(48',
16.23(48)
t . 2 8 ( 7 7)
S.L5(15)
3.89(79)
WILBUR
9238
w
8.66 s.26
8.54
s
4.s2
3.73 s.52
Y
12.56 12.51 s.26
6.52
1.88
9.25
6.96
2.89
Ls.23
ts.60
4.67
14.31
11.2I
6.57
r5.71
I3.83(74)
1 3 . 6 9( 4 8 )
2 5 . 2 6( 4 8 t
2.79(77)
r.24(4e)
7. rs (73)
W I L S O NC R E E K
9327
L{
6.6'7 9.29
6.35
s
2.7s
2.38 5.59
8.95 0.28
v
9.s5
4.1r
r.22
6.38
5.16
I.7g
7. 4 s
?.38
3.24
L g. 4 6
8.57
4.20
11.98(74)
rs.2s (48)
r 7 . 8 4( 4 8 )
2.12(77)
0 . 7 8( 7 s )
4.9r(77)
W I N DR I V E R
9342
w
89.81
9r.59 5.22
s
10.92 S.4g
11.88
Y 1 9 1. 6 8 t 5 3 . 0 4 S . 1 8
62.48
5.77
i7 .6s
77.92 rs3.9s
9 . 3 s 14.44
8 7 . 5 6 I 15 . 0 1
113.90
r8.26
L 2 6. S S
W I N T H R O IP W S W
9376
w
Is.86
10.53 0.35
s
3.9r
3.57 5.4',7
14.71 r4.16 9.28
Y
7.45
2 .r g
I0.24
8.82
2.79
12.24
1 3 .S 1
4.39
r7.97
15.22
6.2r
19.84
16.9t(72)
1 r . 1 6( 4 8 )
24.49(481
2.47 ('77)
r.39(70)
6 . 4 7( 7 7 1
3.52
4.67
1.31
6.54
7.93
2.58
8.12
8.39
3.24
11.11
1r.76(74)
6.01(48)
1 4 . 2 5( s 6 )
l.2s('77)
0.28(7s)
3 . 9 2( 7 9 )
Mean
8959
w
s
v
M e di a n
WAPATO
5.39
1.91
7.3A
5.s5
1.68
6.69
WATERVILLE
9gT2
l{
7.89
8.90 s.29
s
3 .s 4
3 . 3 9 o. 6 1
Y
11.43 1r.13 s.29
WELLPINIT
9958
l,'l 14.19
13.54
s
5.23
5.6S
19.19
v
t9 .'t9
0.26
s.38
9.22
9465
Y A K T M AW S OA P
[{
5.93
5.85 9.34
s
r.77 0.53
1.96
y
7.99
7.82 9.28
1.36
7.14
lg.gr
3 . Z t
s.9r
5.14
B-?7
LZ.Z)
r25.28('12'
23.52(4r)
L 4 A. t 6 l 7 2 )
45.97(77',)
4.62(67)
6 4. s 7 ( 4 4 ' , )
( rDAHO)
ilean
1380
lled i an
cv
ts
Percentiles
75
25
CALDWELL
90
t l a x( y e a r )
M i n( y e a r )
6.56
2.L0
9.27
9.53
3.55
12.37
9.8s
4.26
r3.67
L2.94(43)
5.59(4r)
r 4 . 8 9( 4 3 )
STATION
C O E U RD I A L E N ER A N G E R
1956
w
13.79
t6.29
18.98
19.43 9.22
s
7.22
4.63
5.29
6.78 9.35
,r
t9.52
23.7r
26.19
26.38 0.18
2r.9t
8.82
28.75
z5.ot
IS.5S
32.14
3 5 . 7 0 ( 7 4 1 6 . 8 7( 7 7 )
3.4s(66)
ra.2s(48)
3 7 . 6 8( 4 8 ) 1 5 . 4 5 ( 7 7 )
11.1.4 15.24
7. 6 s
1 2. 7r
2s.14 26.22
I7.3s
1 4. g s
28.75
6.s2(7't)
19.6r(48)
4 . 8 9( 6 6 )
1 6 . 0 4( 4 8 )
33.6s(78) r4.22(73l.
M O S C O W - U N I VO. F I D A H O
6152
l{
17.23
1r.99
16.98 0.24
s
4.25
6.52
5.62 0.34
Y
1 7. 5 9
23.75
23.50 0.2r
15.27
5.Ss
2 g. 4 8
19.90
8.SS
2 7. 4 5
2r.36
9.29
39.56
3 5 . 8 s ( 74 \
12;31(48)
36.25(74'
8 . 1 2 ( ' t7 ' , )
2 . 8 ' 7( 6 6 )
r3.19(66)
6 4 2 4 ' N E Z, P E ' R C E
w
13..go L2.37 9.22
s
8.92
9.13 9.28
v
2r.92
22.Lr 0. 18
Lt.27
7. 3 6
19.59
14.,19
rs.49
24.64
16.74
11.87
27.93
r 8 . 4 0( 5 9 )
1 5 . 2 6( 4 8 )
3s.44(48)
4 . 6 6( 7 7 )
3 . 4 r( s r )
14.94(73)
6844
P A R I ' I AE X P E R I M E N S
TTATION
w
7. 6 4
7.46 0.33
5 .1 1
s
r .63
3.24
3.53 0.44
Y
19.87
7.90
L 0 . 2 9 0. 2 9
6.59
2.12
9.A0
9.16
4.44
r3.35
11.59
5.94
15.69
r 3 . 7 6( 7 8 )
6.2s(65)
16.55(70)
2.22(49)
r " s 8( 4 9 )
3.30(49)
6891
PAYETTE
w
8.22
8.11 9.31
s
2.9s
2 . 9 5 g. 4 3
Y
11.12
11.41 9.27
6.75
r.90
9.t7
1 0 .r 5
3.62
r3.s3
r1.79
4.64
15.15
12.53(44l6.25(4r')
16.9s(41)
r.45 (77)
S . 5 s( 6 6 )
4.79(66)
w
s
Y
7. 7 8
2.92
ro.70
8.s4 0.26
2.85 9.39
L0.79 0.22
377L
GRANGEVILLE
w
12.88 6.23
I3.21
s
Is.20
Is.20 g.3s
Y
23.41
23.39 s.r9
5.32
I .42
7.s7
lg.s2
6.47
1 8 .s 5
r0.15
5. 4 9
16.28
4.79
r.41
7.s3
B- 28
2.33(77)
0.79(77)
s . 1 8( 6 6 )
( rDAHO)
f4ean
tted i an
cv
PORTHILL
7264
t{
13.66 5.24
13.37
7.r2
s
6.72 g.3r
y
2 g. 4 8
2 S. 9 " 1 S . 2 L
7386
Lg
9. 4 9
4.27
14.98
Percentiles
75
25
11.s6
s.69
t8.43
9S
M a x( y e a r )
M i n ( y e a r)
1 5 . 3 6 16.77
9.95
I . 83
22.99, 25.78
5.s8 \77',)
2 L . 8 6 ( 74 1
11.55(42) 3.03(73)
1 1 . 5 2( 4 4 )
2 8 . 9 7( 74 '
P R I E S T R I V E R E X P E R I M E N TS T A T I O N
r7.97
6.13
26.81
21.38
7.68
3s.96
26.38
9.84
35.46
29.69
11.84
37.52
38.52(74) 9.55(77)
16.32(41) 4.68(67)
4 6 . 7 7 ( 7 A ' , ) t 7 . 4 5 ( 7 7)
5.23
5.39
S.2g
7.r5
3.98
11.30
8.12
5.29
15.19
1 1. 8 2
8.r3
18.82
1 3. 5 9
9.s8
20.65
14.79176') s.83(?7)
1 1 . 1 6 ( 4 1 ) 2 . 7 7( 5 r )
24.2r (78) r0.95 ('79)
SAINT I4ARIES
8562
w
22.26 5.22
22.t8
s
7. 8 2
7.39 s.32
Y
3S.gg
39.34 S.19
16.37
5.34
22.79
r8.?5
6.s3
27.97
25.30
9.4'7
32.76
2 7. 7 9
r9.87
37.42
3 4 . 8 7 ( 74 )
1 s . 7 8( 4 8 )
4 2 . 7 7( 4 8 1
9.30 (1',l1
3 . 3 s( 7 7 )
17.92(77)
7.44
4.13
9.59
5.99
12.68
9.9](43)
7 . 2 7 ( 7s ' , t
14.6r(41)
r.7r(77)
S. 3 1 ( 74 )
5.43(77)
t9.27
6.SS
L ) . 1 ,
TI.2S
8.05
18.56
4.32(77)
14.3r(7r)
s . 7 8 ( 74 )
1 0 .r 8 ( 6 3 )
25.35(63',) 9.r4(66)
w
Y
23.79
8.89
32.58
22.96 0.2r
I .36 0.28
32.64 0.16
RIGGINS
7796
w
Is .20
I0.18
s
6.64
6.33
Y
16.84
t7.31
(NEVADA)
ELKOFAA AP
2573
t{
6.31
6.15 S.3A
s
3.33
3.2r 0.49
Y
9.64
9.59 0.25
4.94
t.52
6.27
5.29
2 .t 8
7.38
6.91
2.68
rs.90
8.08
4.54
12.9r
5Og5
P A R A D I S EV A L L E YT N W
w
6.29 5.33
9.69
3.95
s
2.60
L.02
2.49 5.52
v
7.93
9.2s
8.31 0.26
5.18
r.73
7.64
8.48
3.3I
19.88
9.57
4.83
12.57
rr..57(s8)
5.73(52)
t4.87 (52)
2.07(77)
s.46(74)
4. r6 (66)
WINNEMUCCA
9171
l{
5.80
6.sI 0.33
s
2.69
2.47 0.59
Y
8.49
8.7A 0.28
4. 4 8
t.7g
6 . 7r
7.30
3. 4 1
9.87
8.33
4.85
1r.06
9.15(52)
5.43(63)
r3.9s1s2)
r.72('t7)
s.43(54)
3 . 9 3( s 4 )
OWYHEE
5869
w
9.27
9.49
s
5.97
4.66
Y
14.35
t4.11
0.2t
S.4g
0.I9
3.57
L.S0
5.22
B-29
rr.46
(CALIFORNIA)
Percentiles
75
25
cv
TO
9.28
s.48
0.26
6.52
L.7S
9.60
8.56
2.53
rs.54
L r . 7s
3 . 95
14.14
1 4. s 5
5.24
1 7 .3 4
1s.39(63)
8.1?(7r)
22.96(7r)
3.82177)
1.31(77)
7.32(65',t
2T47
C R E S C E NC
T ITY 1 N
w
65.66 5.23
5 1. 6 S
s
7.67
7.25 A.4A
Y
68.51 9.20
6 9. 2 7
43.43
3. 9 9
52.64
52.85
4.52
59.98
7s . 8 6
1S.58
79.96
7 9. 4 9
LI.42
88.43
9r.45(7A')
r5.24(s3)
96.7s(43)
22.36(771
2.36(741
3 5 . 6 4( 7 7 ' i
F O R TB I D W E L L
3157
w
12.21
12.95 b.28
s
3.29 A.42
3.55
Y
15.?5 15.15 5.24
8.3s
I .91
11.25
9.79
2.48
r3.60
t4.62
4.43
18.36
17.Ig
5.64
2r.r7
r8.8S(52)
8.r3(71)
25.5s(7rl
3.82(77)
r.46(62','
9.43(s9)
33.84
r.1s
37.?2
4s.28
2.92
45.28
59.37
5.79
63.s5
6 7. 4 2
72.58
1 4 . s 5 ( 7 7t
9 s . 4 2 ( 74 l
9 . 6 6 ( 7 7 ' , t s . 3 8 ( 74 )
9 s. 8 s ( 74 ' ) 2 3 . 7 I ( 7 7 )
llean
Hed i an
15T4
CEDARVILLE
w
9.83
9.54
9
2.96
3.25
Y
12.74
13.03
3't6I
w
5
Y
H A P P Y C A M P R A N G E RS T A T I O N
5 1. 3 4
4. 3 9
55.73
5 1 .S 3 g . 3 S
4 . 4 6 S. 4 8
s5.63 5.27
9s
7. r s
llax (year)
ilin (year)
TTJLELAKE
9953
w
7 t30
7.51
s
2t94
3.39
v
r0.90
I9.94
9.33
b. 4 7
9.26
4.2r
t r. 5 9
7, 3 6
5.73
2.23
9.97
8.98
4 . 74
12,54
11.18
5.08
14.OT
r2.51(s6)
6.62(58)
r6.07(6s)
2.32(77',t
t.2r(70)
s.88(s5)
YREi(A
9865
!., 15.49
15.87
s
3.27
3.56
Y
1 9 .5 3
1 8. 7 6
s.35
O.AT
0.31
8.8s
1.76
1t.58
1r.25
2.38
13.45
1 9 .5 7
4.23
23.28
21.8]
4.83
23.97
27.ts(14)
7.19(78)
3 0, 9 4 ( 5 6 ' t
4.63(771
s.79(74)
7. s3(55)
B- 30
DESCRIPTIVE STATISTICS
IiONTHLY PRECIPITATION DATA
( l94S-1979)
( oREGON)
P er c e n t i l e s
M e di a r i
Fto
Mean
g3O4
oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
ASHLAND
I.4S
1.74
2.54
2.59
2.83
3.12
2.'16 2.45
I.86
1.9I
I.67
L.9g
1.16
1.37
1.23
I.52
1.I3
0.96
5.04
0.31
0.26
S. 4 5
g.6L
0.83
SDev
CV
Tg
25
75
9s
2.36
3.46
3.9s
4.r2
2.45
2.48
2.Sr
r.82
t.8g
3 .3 3
5.12
5.6s
5.98
3.Ss
3. 1 8
2 . 74
3.73
2.55
1.3S
L.64
8.81
4.58
7.62 13.rS
9. 7 9 1 4 . 3 6
6 . 3 2 14"22
5.96 L0.26
9.68
5.36
6.55
3.72
4.56
1.96
3.22
I .36
1.84
9.39
2.52
0.53
4.62
1.82
12.16
r5.30
1s.84
r7.56
I 5.64
1S.56
1.42
5.29
5.sS
2.56
3.22
5.77
t7.79
18.89
19.33
26.35
21.89
16.8s
8.47
6.76
6.83
4.2s
5.22
6.93
r.Sl
1.45
4.20
t.42
2.65
s.93
1.65
9.75
5.3'7
O.Sr
g.s2
S.s4
16.78
r7.44
ts.13
24.93
L9.29
I5.92
6.82
6.01
6.46
4.19
5.2s
6.89
0.98
r.52
r . 74
1.37
r. s4
1.82
2.35
1.75
1.26
L.28
1.89
2.06
g.7s
t.oo
0.74
1.58
L.47
3 .r {
2.84
1.75
1.36
1.s2
3.15
2.54
3.46
3.29
1.51
3.28
4.27
4.36
3.52
3.31
2.85
3.9s
g.Sg
0.gS
s.23
s.t7
g.sL
s.s4
S.g5
0.s5
g.ss
S.ss
A. O S
s.0s
3.r5
2.54
3.23
3.12
r.50
3.24
4.22
4.31
3.52
3.31
2.80
3.9s
0.48
1.19
s.76
0.85
o. 4 3
s.32
o.08
g.ga
g.sg
s.g4
s.69
1 .1 7
1.66
1.43
t.24
1 .1 6
s . 74
s.56
s.30
s.s0
o" 9 3
0.30
9.55
1.ls
A S T O R I AW S OA P
9328
3.79
oct
7.92
6.13
3. 9 7
N o v I S . 4 2 1I . 2 8
3.52
Dec 12.99 12.37
5.lS
Jan lS.75 10.36
4.15
7.98
Feb
8.85
3.11
7. 4 2
Mar
7.59
I.79
5.I8
Apr
5.05
1.59
2.74
May 3.94
I . 54
2.5'7 2.23
J un
L.S5
9.88
1.]9
Jut
1"24
Aug
1.25
1.61
1.84
sep
3.Sl
3.25
0.54
s.38
s.29
s.47
s.47
s. 4 r
0.35
s.49
s.6g
s.88
9.77
9.57
2.48
4.86
6.66
4.98
5.26
4.34
2.63
t.44
0.84
s.16
s.31
0.62
s.68 0.94
o. 6 r s . 5 6
o.s8
9.24
0.38
s.36
a.2r
s.26
g.r4
s.48
s.2g
s.93
0.0s
s.o3
S.31
g . 7r
0.64
9.68
0.42
0.44
g.5s
9.72
9.70
0.14
g.16
0.16
B A K E RK B K R
0.52
0 . ' 12
l.g7
I.S9
1.24
l.S2
l. 13
1.I0
0.14
9.75
5.77
0.88
0.84
S.9I
1. 16
I.46
1.35
l.S8
0.32
S.6g
g.4S
9.62
g.4I
9.65
0.78 0.63
s.65 0.59
0.38 0.52
s.62 g.71
g.7t s.78
t.s2 s.69
o.96 S.7t
o . 74 t . 2 2
9.64 l.s3
s.78 1.11
Range
o.23 7.29
o.as 7.74
9.68 rg.6s
s.5s 5.59
9.25 4.49
0.r3 5.22
0.33 3.gr
0.19 5.12
0.ss 3.68
s"gg 2.52
g.gs 3.98
g . g 0 3 . 74
0.86
0.66
5.65
0.56
5.49
5.55
g. 6 1
0.84
5.87
I .67
1.37
0.99
g4T7
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
JuI
Aug
Sep
l,lin
7. 4 3
7.74
1r.28
6.SS
4 . 74
5.35
3.34
5.31
3.68
2.52
3.08
3 . 74
1. 4 9
r.72
2.93
1. 5 s
s.94
L.04
0.84
r.28
s.98
g.5r
g.61
0.82
o.6s
r.12
llax
B-31
s.45
r.s7
s.9s
r.28
(oREGON)
Percentiles
Mo
l,lean
lted i an
TS
25
75
9g
Max
l,lin
Range
2.39
5.45
6.73
6.96
5.12
5.36
2.30
t.5S
5.54
s.LS
o.s8
I .81
7.r7
1 1. 2 9
13.?9
r3.38
9.70
9.58
L2,98
rs.41
r6.98
12.67
9.38
0.59
9.69
s.77
r.14
l.3s
0.65
1.28
2.88
4.44
4. 2 6
3.79
3.14
1. 4 6
s . 74
0.22
o.s4
g.gg
s.2s
8.86
5.42
4.58
1.92
0.75
I .18
2.59
L S. 6 6
7.69
6.92
2.63
L.g2
2.99
3 . 45
L5.32
23.35
2 5 .5 6
29.t4
t7.74
r2.48
1r.3s
7.31
4.39
2.65
4.39
4.55
0.59
r .08
I .63
2.32
2.26
1.57
s.67
9.27
s.s7
g.ss
s.SS
0.50
14.73
22.27
2 3. 9 3
I7;82
15.48
19.91
10.68
7,94
4.32
2.65
4.39
4.55
r .s3
r.26
1.64
1 .r 8
s.66
9.65
s.49
9.95
s.88
9,48
s.65
s.44
r.2s
0.8r
s.88
S.6S
s.65
5.82
t.gs
5.94
g.89
1.15
r.07
1.11
s.L2
s.18
o.41
0.63
g.16
g.Is
a.g6
0.r0
s.s4
s.gg
s.sg
s.gs
9.34
I .58
0 . 74
s.93
0.44
s.22
0.I4
0.37
0.25
g.s6
0.92
9.05
0.96
2.42
2.52
2.88
I .48
t.l2
1.94
3.38
3.82
3.48
1.86
1.60
1. 9 1
2.t5
2.26
r.23
I .64
9.96
5.88
4.58
8 . 74
4.37
2.59
2.76
2.r8
3.76
3.25
r . 74
2"18
r.82
s.gg
s.g2
g.ss
9.20
s.g7
0.gl
g.sg
s.09
o.ga
g.sg
0.s0
s.gg
5.88
4.56
8.14
4.17
2,43
2.75
2.18
3 . 76
3.25
r.74
2.18
r.82
4.29
6.Lg
5.88
5.86
4.7s
3.85
3.79
3.23
I .53
0.65
9.53
5.45
5.46
s.46
9.42
0 . 70
0.78
I.Sg
2.t4
4 .1 6
5.71
5.59
4.54
4.46
I.52
s.85
s.t4
1.5S
1.86
I.4I
0.85
s.29
8 . 74 r t . S 2
3.54
6.99 15.69 18.72
8.12 I7.78 2I.r0
8.61 L6.45 27.99
6.43 t2.25 I 5.96
6.44 11.64 14.43
?.s8 rs.84
2.59
8. s2
1.93
5.98
1.94
3.57
s.59
s.s8 0.99 r.2s
3.64
0.s7 r.46
g. 6 4 3 . g s
5.21
21.93
25.0r
23.65
25.77
24.76
17.91
1 1. 4 3
14.15
7.72
6.49
6.97
1.38
0.L6
1.86
2.rS
2.57
2.82
1.59
5.46
g.12
S.g2
A.gs
0.s0
g.S2
2r.77
2 5 .I 5
21.55
2 3 . 7g
2L.94
t6.32
16.97
r4.93
7. 7 s
6.4s
6.97
7. 3 6
1.t4
2.ss
3.r1
2.gs
t.72
1.98
0.88
s.57
s.J0
0.gs
g,s0
0.s3
6.46
r.68 4.26
3.12 7.52 9.22
4.17 9.73 12.56
4.36 1S.35 11.88
8.08
3.38 6.23
2.90 6.As 7.I0
4.32
1.56 2.9I
3. 4 4
L.S4 2.64
0.52 1.32 2.52
0.66
0.02 s.55
r .98
1.04 0.87
3.25
0.75 2.16
9.79
18.28
19.16
15.5r
11.84
8.87
4.94
3.94
3 . 84
2.'12
5.24
3.96
9.88
9.31
r;47
9.96
s.79
0.59
0.55
S.16
0.a2
0,96
g.gs
S.0S
8.82
7 7. 9 7
1?.69
14.55
r1.05
8.28
4.39
3.?8
3.82
2,72
5.24
3.96
SDev
BANDON
2 NNE
O47I
4.13
3.43
Oct
4.96
Nov
8.85
4.39
8.67
4.99
Dec I0.19
9.84
8.91
4.72
Jan 10.11
Feb
7.39
7.79
3.59
Mar
7.82
7.74
2.13
Apr
4.24
4.29
2.53
May 2.8s
2.34
I.93
Jun
I.26
I.SA
0.97
Jul
9.45
S. 2 5
0.5I
Aug
I .39
I.S3
0.8s
Sep ].81
I.74
1.18
9694
Oct.
Nov
Dec
Jan
Feb
Mar
Apr
May
J un
Jul
Aug
Sep
1955
Oct
Nov
Dec
Jan
Feb
Mar
Apr
t4ay
Jun
Jul
Aug
Sep
BEND
9.86
I.55
1.85
1.95
l.g2
0.79
0.59
1.01
g.99
0.41
5.50
0.45
0.53
I.32
I.52
L.9'7
9.98
9.66
0.34
9.66
0 .'19
0.24
5.25
0.27
BROOKINGS
6.64
5.94
I1.51
10.88
I3.I9
I4.24
12.79 11.84
I9.27
I0.45
9.25
9.27
5.43
4.56
4.13
3.30
1.52
1.01
5.59
S.I9
I.g6
5.42
2.I'7
l .64
s.69
0.5r
o. 4 8
g. 4 7
s.46
r.s9 r.85
] 8 6 2 C O R V A L L I S - S T A TUEN I V E R S I T Y
Oct
3.47
2.85
2.16 5.62
Nov
5.84
5.82
3.28 0.56
Dec
7.26
6.70
3.89 9.54
Jan
6.95
6.84
3.82 9.55
Feb
5.03
5.12
2.46 5.49
Mar
4.44
4.39
1.92 g.43
Apr
2-28
2.56
l. I8 5.52
May I .89
2.52
I .09 0.58
g.9I
Jun
I.12
0.E7 5.18
Ju]
0.37
O.t9
0.52 1.41
g.3S
Aug
5.72
1"93 t.il{
sep
1.52
l.A0
7.gS 0.7I
o.o2
o.o2
B-32
s.7s
I .47
t.56
6.66
1.14
0.58
(oREGON)
Percentiles
lilo
llean
lted i an
SDev
cv
C R A T E RL A K E N P S H O
1946
3.73 0.68
5.24
oct
5.55
5.35 0.55
Nov
9.79 19.22
6.61 6.5s
Dec lI .19 1I.14
4.64 9.42
Jan IL.Sg I1.44
3.52 s.43
8.13
Feb
8.24
3.16 g.4s
Mar
7.82
7.53
2.La s.48
4.61
Apr
4.58
s.62
2. II
2.92
ilay
3.42
g.5S s.8s
I.6S
2.32
Jun
O.5O 9.74 r.15
Jul
5.64
I.25 1 . 1 4
Aug
5.56
1.l9
I.77 9.82
1.86
Sep
2.15
25
lg
75
9g
li!in
Range
L.76
2.52
5.4r
4.97
3.86
4.45
L.9A
L.42
g.5g
g.gg
g.gg
0.25
6.76
3.12
5.67 13.10
6.72 15.93
7.60 t4.24
4 . 7 2 L9.92
9.85
5.s8
5.88
2.85
4.44
1.84
3.97
1.14
0.83
o.g4
r.88
s.g6
2.89
9.66
L0.0r
15.10
18.35
L7.22
13.05
12.56
7.54
6.94
4.66
1. 8 I
2.58
4.98
19.1I
24.t6
38.47
25.93
r7.58
15.22
9.63
8.75
9.25
2.87
5.34
6.83
0.31
g.L4
S.9S
2.43
3.31
L.24
r.29
S.61
0.ss
0.0s
S. 5 0
0.SS
18.80
24.02
37.57
1 8 .s 9
t4.2r
13.98
8.34
8.49
9.25
2.87
5.34
6.83
s.3s
s.26
s.45
s.42
9.24
g.3s
s.26
o.3s
9.r8
s.s0
9.42
9.64
5.68
S.7S
9.53
s.65
s.59
9.76
0.4s
g.s4
o.sg
g.g9
r.29
1.54
r.72
r.6a
t. 14
I.30
r.56
2.37
1.88
9.62
s.87
s.84
1.75
1.94
2.26
2.36
1.78
r.72
2.94
2.77
2.30
I.42
1.59
r.03
3.11
3.41
3 .s 8
3.27
2.78
2.55
2.78
3.68
3.87
2.52
3.25
2.33
S.gg
g.s3
s.23
s.27
s.s7
s.23
0.19
0.22
S.Os
g.Ss
0.OS
0.gs
3.r1
3.38
3.35
3.sA
2 . 7r
2.32
2.59
3.46
3.87
2.92
3.25
2.33
19.9r
r5.79
1 3 .5 9
15.68
r3.45
8.61
4.49
4.86
2.77
1.51
4.02
3.41
0.53
I.9s
l. s7
r.38
0.77
0.s8
s.39
9.1r
g.s4
0.gg
g.s0
O.Os
10.38
13.89
t2.s2
14.3s
12.68
8.03
4.rS
4.75
2.73
1.51
4.92
3.41
14.83
1 9 .s 8
21.36
2L.LS
15.23
13.81
rs.65
I.r2
7. 0 6
2.38
'4.42
7. 1 4
2s.2r
23.95
28.62
24.r9
29.95
22.53
r4.21
ts.82
9.6s
3.39
6.48
t2.7r
0 . 6 7 1 9 .s 4
r.6g 22.35
3.87 24.15
3.29 2s.90
2.45 18.45
2.37 25.16
1.62 L2.59
9.95
s.87
9.14
9.46
3.39
s.ss
6.48
0.65
g.r4
12.5'l
2T68
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
DAYVILLE
5.68
0.90
1. I8
1.17
I.26
1.31
1.19
I.25
5.76
O.9S
1.gI
9.89
9.89
1.98
1.39
I.53
1.19
9.92
O.47
0.28
9.38
9.62
9.52
9.54
2997
OcE
Nov
Dec
Jan
Feb
l l ar
Apr
l,tay
Jun
JuI
Aug
sep
F O R E S TG R O V E
2.33
3.35
3.76
3.34
6.58
6.80
7.30
3.57
7.7I
7.72
3.?5
7.69
2.64
5.lg
5.56
2.64
4. 9 2
4.89
I .29
2.38
2.39
l.SB
1.56
1.86
9.72
I.I4
1.I4
9.42
5.32
9.45
0.89
S. 5 9
S, 8 4
I.I1
r.66
1.63
9.62
s.49
s.46
s.49
s.48
s.42
0.5s
0.58
9.63
s.93
r.06
s.68
1.14
2.62
2.58
2.52
2.22
2.28
9.80
9.78
9.20
g.s3
a.s6
6.62
5.32
2.24
8 . 4 4 L S" 9 6
4.LS
4 . 7 A r O. 9 4 1 2. 3 8
4.95
9.94 13.62
8.3s
7.26
3.96
7.68
6.39
3.25
4.r4
3.45
r.4s
3.43
2.56
r.o2
2.18
1.54
0.57
1.03
9.88
s.06
1.89
1.32
s.r2
3.15
2.58
0.7a
CTA } I P
GOVERNMEN
3492
4.46
?.18
ocE
7.74
5.79
N o v I I . 4 6 L g. 6 2
6.lS
Dec 14.24 I3.6S
6.44
Jan l 3.66 12.95
4.25
Feb
9.94 15.28
3.99
9.36
Mar
9.22
3;04
6.76
Apr
6.78
2.2I
4.66
l,tay 5.55
2.LG
3. ' 1 9 3. 4 4
J un
9.94
5.75
l.Sg
JuI
f.68
1.91
Aug
1.78
' 3 -4 2
2.65
sep
3. 9 0
9.58
0.51
g.43
s.49
a.42
s.43
g.45
g.44
9.57
9.95
5.95
9.68
2.41
3.8s
6.3A
4.5s
4.88
3.48
2.80
2.55
r.48
s.gs
0.s8
o.78
4.24
7. 2 4
9.6s
7.81
6.91
6.66
4.64
3.69
2.39
s.L8
0.62
1.88
9.66 0.73
g. 7 1 0. 6 L
s.73 s.56
0.70 9.56
s.58 5.64
9.55 0.54
0.69 s.64
s.97 5.63
0.94 9.79
s . 5 6 1 .1 8
s.74 1.19
0.57 0.95
Hax
s.s2
s.ss
s.s8
B- 33
9.25
r6.48
19.06
19.24
13.32
r1.3s
8.84
6.24
4.78
1.54
2.52
5.92
(oREGON)
Percentiles
ilo
l'lean
3827
Oct
Nov
Dec
Jan
Feb
ilar
Apr
May
Jun
Jul
Aug
Sep
HEPPNER
1.19
l.S7
l.6S
1.68
I.6S
1.65
1.43
L.3g
l. I9
l. 11
L.26
1. 16
1.25
O.96
1.44
L.24
t.f5
9.98
5.37
O.16
9.63
0.28
5.77
O.56
4596
Oct
Nov
Dec
Jan
Feb
ilar
Apr
itay
Jun
Jul
Aug
seP
KLAI.IATHFALLS 2 SSW
g.9S
1.17
I.S5 g.9g
I.72
I .64
I. 16 0.67
2.37
I.80
I.82 9.77
2.12
I.79
L.24 S.58
1. 3 6
I.22
0.84 9.62
I.25
5.93
0.93 0.74
g.61
9.72
5 . 5 3 g . 74
g . 9 2 A. 8 6
l.g7
0.86
9.86
5.77
S.7g 0.81
g.lS
0.25
0.35 I.4g
5.56
0.2s
0.79 I .41
9.56
0.38
5.66 I .18
4679
oct
Nov
Dec
Jan
Feb
Mar
Apr
ilay
Jun
Jul
Aug
seP
L A K E V I E T2
{ NNW
L.27
9.94
L.25
1.34
1.1S
1.68
L.79
1.54
2.IL
1.85
I.27
2.16
I.58
7.49
9.86
g.8O
1.46
1.34
I .15
O.9S 0.7I
1.59
1.31
L.gg
1.44
1.14
1.28
0.28
0.13
0.38
g.L6
g.7g
0.43
9.59
9.46
0.55
5L62
oct
Nov
Dec
Jan
Feb
Mar
APr
l4ay
Jun
JuI
Aug
seP
I'IALHEURREFUGEHDQ
g.?6 s.98
5.78
9.46
l.S6
5.82
9.85 o.8g
5.97
5.89
9.68 s.7r
L.g4
0.93
S.7g s.68
9.65
5.52
0.48 s.73
D.78
9.62
0.54 s.69
e.50
S.48 9.82
9.59
l.S4
0.96
9.62 g.6s
L.gg
5.92
5.14 0.74
0.l8
9.33 I .16
9.29
0.51
9.28
9.79 I .56
9.58
9.46
9.62 L.g7
lled i an
SDev
CV
Tg
25
75
9g
o.84
s.9r
s.86
s.81
9.64
0.65
s.85
g.7r
0.5'l
5.54
0. 5 6
9.57
s.52
9.68
0.52
9 . 94
0.86
s.82
9.88
S.6t
o.9g
s.4s
o.76
g. 6 3
s.78
1. 0 8
1.2I
0. 8 1
s.25
s.42
9.65
s.6g
0.3r
0.62
9.26
s.38
9.22
0.gs
g.sg
9.0s
0.66
g.7I
9.34
s.g6
o.g8
0.26
r.6s
2.t6
2.99
1.78
1.45
1.44
L.9s
2.24
I.74
s.72
1.S1
I.22
2.28
2.64
2.48
2.67
2.Lg
r.89
2.46
2.69
2.66
L.IS
1.84
I .56
3.64 s.S6
3.94 S.Os
4.45 5.34
4.94 0.31
2 . 3 5 S. r 9
4.58 0.41
3.78 S.g7
3.27 0.52
2.89 0.06
I.24 g.ss
2.9r g.os
2.24 S.gS
3.58
3.94
4.06
3.73
2.tr
3.67
3.71
3.25
2.83
I.24
2.9r
2.24
0.18
0.44
S.38
9.72
0.90
0.36
g.4t
g.16
s.l9
0.06
0.90
0.s0
s.s2
1. 1 6
0.68
0.57
0.27
0.38
0.25
0.gl
g.s4
g.t7
1.66
2.63
3.39
2.64
r .92
r.8g
1.1S
1.48
r. 31
g.4s
g.'15
0.54
2.58
3.41
4.80
4.97
2.46
2.85
r.53
r.9s
t.74
0.76
1.75
I .34
4.55
4.19
8.93
4.85
3.89
3.47
2.Sg
4.75
3.09
r.60
2.93
3.06
0. S g
g.og
5.22
5.56
S.O8
g. 5 8
5.08
S.sr
S. s 0
s.g0
0.ss
g.ss
4.55
4.19
8.71
4.29
3.81
3.39
r.92
4.74
3.59
r.6a
2.93
3.06
9.18
0.32
9 . 74
0.88
s.48
s.48
s.34
g.5s
s.ts
g.s0
g.gs
9.45
5 . 74
1.14
L.32
S. 9 6
g. 8 4
9 . 74
9.86
s.38
0.sg
g.g2
s.gs
o.r7
r.57
2.25
2.57
2 . 85
2.31
1.82
1. 5 4
2.30
2.99
0.38
s.44
s.86
2.45
3.OS
3 .s 4
3.72
2 . 74
2.62
2.22
2.67
3.25
0.90
r.32
r.55
6.62
4.59
8.96
5.8r
3.34
3.84
2.96
4.35
5.47
l .. 3 9
3.04
r.98
S.Sg
0.Sr
s.Or
5.29
S.rl
9.26
0.19
0.32
g.gS
0.s0
g.09
S.SS
6.62
4.58
8.95
5.52
3.23
3.58
2.77
3;98
5.4'l
1.39
3.04
1.98
g,g8
0.L2
a.33
0.31
0.r1
o.22
0.99
0.3s
0.r2
s.0g
g.gs
g.6g
9.24
0.49
9.48
5.55
9.28
0.3s
9.22
s.52
0.33
9.93
s.s6
g.o8
1.10
1.64
1.26
I.18
t.s7
L.2g
9.78
1.34
0.92
s.43
0.58
s.B2
1.89
2.36
r.62
1.87
r.24
1.64
r . 18
r.9s
I .56
0.70
t.s9
1.28
3.54
3. 4 s
3.39
3.35
2.94
2.07
2.23
2 . 70
2.la
1.32
A.EO
3 .1 2
g.gs
0.98
s.66
0.7t
s.59
4.54
0.55
9.62
0.63
0.89
1.37
1.63
s.92
s.7s
s.6s
s.9s
r.96
B- 34
Max
l{i n
s.os
0.s9
s. 1 3
g.at
g .r 1
g.g0
0. o g
g. g g
o.sg
g.sg
s.ss
Rang,e
3.54
3.49
3.3A
3.22
2.s3
r.96
2.23
2 . 7s
2.14
I.32
4,99
3.r2
(oREGON)
Percentiles
Mo
llean
lrledi an
cv
25
75
90
3.22
6.54
7. 38
5.51
4.20
5.54
3.42
2.28
1.17
s.96
s.13
r.29
7.91
r3.58
15.24
15.62
Lr.gs
9. 9 5
6.36
5.20
3.16
0.64
r.93
3.8S
15.49
15.15
r9.48
r7.5s
I3.38
1l .25
7.38
6.86
5.04
1.5I
2.85
5.14
18.28
22.54
26.94
23.62
t9.s7
14.33
9.27
9.39
7.74
s.t6
r.s5
2.24
2.35
1.91
1.4r
1.88
0.9r
s.gg
5.93
S.Sg
6.74
g.ss
6.74
9.56
0.59
0.65
s.64
s.82
s.94
L . 76
1.39
r.g7
s.38
s.68
1.05
r.17
s.63
9.82
s.37
s.22
0.gs
s.sg
0.00
o.15
g.6r
1.50
r.71
1.69
1 .r 8
r.g3
9.58
5.45
0.15
s.0s
s.03
5.23
2.19
3.99
3.9s
4.85
2 . 74
2.98
1.64
1.63
I .25
g. r 7
9.40
0 . 83
3.gS
5.34
5.58
5.88
3 . 5r
3.62
2.24
2.37
1. 6 9
s.9a
1.13
I .57
9.16
7. 2 s
t2"72
5.19
5.37
5.54
3.57
4.22
2.90
1.53
2.83
4.22
0.0t
0.06
0.36
S .s ]
0.21
9.29
g.16
S.rr
0.og
0.Sg
0.sS
0.00
9.r5
7.I4
t2.36
5.68
5 .1 6
5.25
2.9r
4 .r 1
2-99
r.63
2.83
4.22
3.2s 0.53
4 . 6 1 S. 4 7
4.65 5.39
5.69 9.51
3.54 0.42
3.22 S.4g
2.32 9.48
I.61 0.5I
1.63 0.7s
s.68 g.8g
1.38 L.S5
I.8t
s.67
2 .1 4
3.61
5.43
4.89
3.56
3. 6 8
1.88
r.l7
s.86
s.L4
0.t4
s.48
3.59
6.73
8.99
5.74
5.63
6.14
2.96
r.93
L.22
0.26
s.39
1.45
7.58
12.92
L 4. 8 2
14.86
15.62
9.63
6. 4 9
4.14
2.?7
1.17
2.9s
3.6s
II. I2
15.64
18.42
1 8 . 84
13.23
L2.62
8.07
5 . 72
4.86
I.70
2.92
5.54
IA.Lg
22.13
22.68
24.24
16.64
I4.47
LS.I7
7.13
6.88
3.3s
7.69
7.25
1.91
1.99
2;88
r.79
2.66
1.3s
t. I2
0.61
s.rA
0.00
S.g5
S.O3
I3.09
29.14
19.8s
22.45
r3.98
13.12
9.55
6.52
6.74
3.30
7.55
7.22
I.gg
1.80
2.86
2.36
2.58
1. 8r
9.98
s.93
0.4r
g.go
s.s3
s.09
2.2L
3.99
4.79
4.l3
3.66
2.92
1.56
1. 1 9
s.77
g.g9
0.L5
s.93
4.26
6.2I
7.6s 19.63
tg.g4 It.s2
9.57 11.69
5.63
6.42
5.94
7.59
3 .3 5
4.sA
2.79
3.88
2.16
2.89
9.75
1.14
1.55
2.55
3.56
3.86
9.75
14.40
12.92
15.22
ts.99
8.37
5.67
4.97
3.42
2.27
4.25
4.87
0.48
r.J.3
1.36
g.9s
s.43
1.31
0.sS
s.76
S.S3
g.0g
0. g s
g. 0 s
9.22
13.27
11.56
14.32
1s.56
7. s 6
5 .l 7
4.2L
3 .3 9
2.27
4.25
4.8'l
SDev
tg
I , T C K E N Z IB
ER I D G ER A N G E RS T A T I O N
5362
oct
6.gg
5.14
3.84 5.64
I.A2
Nov 19.53 LI.42
4.72 0.45
4.03
Dec II.88
11.52
4.36
5.88 O.5g
Jan 15.93 11.8S 5.39 9.49
4.66
'
4
.
9
9
Feb
I .og
8. 14
9.51
3.36
Mar
7.52
7.78
3.13 5.42
3.tl
Apr
4.80
4.46
1.92 g.49
2.56
May 3.85
3.48
2.97 O.54
L.4g
Jun
2.52
2.48
L.74 9.69
O.5I
Jul
S. 5 5
0.38
9.59 I.g7
S.g0
g.Og
Aug
1.19
9.74
1.31 1.10
Sep
2.62
2.52
I.74 9.66
S.3O
5429
Oct
Nov
Dec
Jan
Feb
fqar
Apr
May
Jun
JUI
Aug
Sep
T 4 E D F O RW
DS OA P
l.8g
1.35
t.8S
2.92
2.43
L.9g
3.44
2.89
2.43
3.25
2.64
1.82
2.15
2.94
I.27
I.83
1.49
L.zg
g.7I
1.11
9.86
I.31
l.0I
L.S8
0.80
9.59
5.75
0.24
0.54
9.42
S.41
0.26
9.56
0.72
9.54
0.78
6032
NEWPORT
Oct
6.52
5.99
Nov
9.75
9.28
Dec ]I.98
12.89
Jan
I0 .89
10.31
Feb
I .44
8.11
l'1ar
8.96
8.25
Apr
4.81
4.59
May
3.16
2.86
Jun
2.31
l.8S
Jul
0.85
9.74
Aug
1.32
A.82
Sep
2.7I
2.59
6749
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
PORTLAND
KGW-TV
3.71
3.29
2.13
6.33
6.15
3.15
7.25
6.74
3.SA
5.84
6.97
3.81
A.64
4.41
2.f3
4.56
4.61
1.91
2.63
2.63
I .28
2.22
l.7A
1.19
1.49
1.22
0.92
0.55
5.34
S.5g
I.04
S.61
l.S7
2.03
1.66
1.43
L.g0
9.65
s.7r
s.57
0.50
4.42
0.56
g. 4 6
s.42
0.49
0.54
s.62
I.00
r.02
g.7I
B- 35
llax
llin
2.3r 0.ss
Range
r8.r2
27.49
24.75
2t.27
r7.r6
L2.92
7.39
8.48
7.7,4
2.3r
5.93
(oREGON)
Percentiles
Mo
llean
7331
oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
J.ul
Aug
Sep
R O S E B U RKGQ E N
2.82
2.13
2.24
4.72
4.48
3.17
5. 9 5
5.76
3.25
5.62
5.73
2.93
3.91
3.52
2.L7
3.45
I.62
3.33
2.02
1.85
1.11
I.70
I .51
0.93
I.05
9.52
1 .l 2
5.24
O.gB 9.49
0.53
S.16
9.73
g.8S
1.gB
0.98
8797
oct.
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
sep
VALE
0.7'1
0.99
1.11
I.23
0.9I
9.13
0.72
0.98
A.79
g.2I
9.44
0.53
9.50
5.78
1.f4
1.14
9.90
9.59
5.54
9.77
0.54
S.S6
9.25
0.49
s.79 t.s4
s.67 9.57
g.69 0.54
9.64 0.52
s.65 0.72
s . 4 9 S. 6 ' 7
o.?3 1.91
0.78 s.79
0 . 6 6 S. 8 3
0 . 3 3 1 .s 9
9.64 I.47
9.62 t.r5
8997
Oct
Nov
Dec
Jan
Feb
llar
Apr
May
Jun
Jul
Aug
sep
WALLOWA
I.69
I.52
2.92
I.97
2.I3
I.94
I.85
1.57
].43
1.38
I.49
1.46
1.45
].48
1.88
1.49
1.66
1.35
0.68
9.56
9.82
9.68
I.30
1.1S
0.96 S.6g
r . s 9 g. 5 4
r .28 S.6S
r.1s 9.60
s.67 9.47
0.66 5.44
s.75 0.5I
0.98 5.52
t.07 s.64
s.62 S.9I
0.69 9.84
1.14 S.88
9668
Oct
Nov
Dec
Jan
Feb
Flar
Apr
May
Jun
Jul
Aug
Sep
WASCO
5.99
0.7I
1.14
1.94
l.6g
1.64
f.78
I.A0
f. f9
L.g2
0.96
A.83
9.69
6.73
g.6S
0.7I
g.Aj
9.63
9.25
0.29
9.35
5.26
S.51
5.46
s.88
9.92
o.95
r.93
g.9b
s.58
9.52
s.58
9.56
s.3l
s.43
9.42
M e di a n
SDev
cv
IO
25
75
9g
0.86
s.67
0.55
9.52
o.56
s.47
9.55
s.54
I.07
2.gs
r .37
s . 74
9.94
L.A6
2.r3
r .47
2.38
3.58
3.29
2.53
2"49
I.S2
0.93
0.26
3.6s
6.26
7.34
6.96
4.67
4.56
2.55
2.40
1.55
s.32
s.84
l. 38
5.A7
8.41
9.29
lS.3s
6.75
6.OS
3.6s
3 .t 1
2.4I
0.53
r.26
2.29
12.53
15.91
15.74
11.29
9.7r
6.65
5.28
3.8s
4.97
2.79
3.35
3.15
s.96
r .48
1. 3 8
I.60
1.56
t.gs
9.95
I.40
r.35
0.24
s.50
2.L5
2.s3
2.54
2.92
r.84
L.4s
1. 3 5
2.59
l.?8
g.6t
s.93
r.s6
3.s3
2.54
2.48
3.s7
2.25
2.2s
4.s7
3.33
2 .t 9
1.36
3.L2
2.9r
0.89
0.53
0.6s
S.58
s.76
S.6s
0.'t5
0.81
9.88
1.16
I.I8
0. 8 1
r.9s
1.34
L.25
9.75
0.66
s.L2
g.ss
o.st
s.gs
0.sg
s.14
0.54
g.t0
9.22
s.32
s.44
g.I4
s.l9
g.I9
o.14
o.gA
0.24
A.43
S.6s
0.88
g.3s
s.38
0.29
0.34
g.3s
0.ss
5.sI
g.g0
g.gg
0.gg
ilax
.lli n
Range
S.L4 12.39
S.ll
1s.80
5.84 t4.95
1.35
9.94
I.S2
8.69
9.47
6.18
4.79
5.49
9.30
3.55
g.g0
4.97
2.79
S. S g
S.gS 3.39
g. O r
3 .1 4
0.sg
s.12
g.16
s. r 5
s.s2
3.53
2.42
2.32
2.92
2.23
g.g9
9.SI
o.s4
-9.s0
s.00
9.00
2.LL
4.06
3.29
2.I9
I.36
3 .r 2
9.r5
s.58
s.34
9.84
s.64
s.68
0.63
0.80
0.38
s.83
s.49
s.07
s.08
s.08
r.9.5
I .25
I.23
5.97
9.95
l.s6
1.r2
1.12
9.90
9.20
9.25
0.45
2.rt
2.72
2.82
2.6t
1.89
r.88
1.82
2.66
2.L8
s.84
r .28
r.82
2.64
3. 5 4
3.55
3.52
2.13
2.62
2.t4
3.42
3.48
1.6s
1 . 9r
2.64
4.32
4.94
7.92
4.79
3.6'7
3.55
3 . 74
3.89
4.45
2.56
2.24
{.43
g.gs
s.Ss
0.25
S.]8
s.32
g.S7
S.g7
9.38
0.18
g.Sg
9.s0
fl.SS
4.32
4.94
6.77
4.52
3.3s
2.98
3.67
3,5I
4.27
2.56
2.24
4.43
9.24
9.49
0.55
0.58
g
28
s ". 2
4
5.rg
0.08
e.96
g.s0
g.gg
0.06
o.4s
1.34
s.98
2.24
2.39
9.65
l. I1
2.49
0.s8
I .48
0.6s
L.26
0.95
9.26
s.26
5.96
e.l8 ,1.02
g.ss
9.42
g.0g
0.62
g.2r
g.'lg
1.96
2.84
2.96
3.97
2.59
I .59
I .28
1.75
r .48
9.65
9.95
r.g6
3.89 9.sS
3.76 0.s6
3.84 9.35
4.77 0. 18
4.37 S.gr
3.08 S.s9
2.t4 S.S2
2.67 S.SI
1.98 g.S0
1.36 S.Ss
1.54 0.0s
2.58 s.Ss
3.89
3.7s
3.49
4.59
4.36
2.99
2.L2
2.06
r.98
1.36
1.54
2.98
B-36
0.ss
2.9r
(t{ASHTNGTON)
Percentiles
Mo
M e a n M e di a P
gOSS ABERDEEN
6.63
OcE 7.59
Nov IA.86 Ig.9g
Dec I3.54 13.30
Jan 12.24 12.59
Feb
8.63
9.52
8.08
Mar
8.79
5.49
Apr
5.55
3.42
May
3.48
2.47
2.44
Jun
I.Og
I .39
Jul
Aug
2.93
I.66
3.39
Sep
3.70
9554
oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
12 3 3
OcE
Nov
Jan
Feb
lla r
APT
lrtay
Jun
Jul
Au9
SeP
I 395
Oct
Nov
Dec
Jan
Feb
Irlar
Apr
May
Jun
Jul
Aug
Sep
BELLINGHAM
2
3.64
3.50
4.73
4.46
4.82
4.62
4.50
4.28
3.06
3.38
2.96
2.72
2.42
2.49
2.OB
2.93
1.49
I .71
9.94
I .08
g.9I
I .44
1. 8 7
2.93
C E D A RL A K E
9.63
9.92
r3.3s 13.18
14.82 15.I4
13.4t r4.36
r0.9r r0.35
r g. 2 2 r s . 6 2
8.28
5.94
5. 3 1
2.32
2.95
5.54
8.06
5.22
5.s6
2.24
I .87
5.03
C|EWELAH
7.66
I. 17
2.48
2.40
2.99
2.58
2.32
2.39
I.80
1.80
1.65
1.61
r.39
l.I2
I.87
l.7g
I .44
I.42
g.6l
9.76
0.95
0.58
1.1S
0.92
Lg
25
75
99
l,lax
ilin
Range
4.56 s.54
3.8? s . 3 6
3.83 9.28
5.55 0 . 4 5
4 . 9 8 0. 4 3
3 . 5 9 0. 4 s
2.13 0.38
1.83 s.53
L.41 s.6s
I.19 s.86
f.48 9.73
2.39 s.6s
2.82
5.75
8.36
5.44
4.94
4.87
2.64
1.28
0.76
g.L9
0.32
s.82
5.25
7.96
11.32
8. 37
6.89
6.34
3.92
2.r7
l.19
9.41
9.72
2.08
8.88
14.15
15.83
14.25
1r.85
11.21
7.sg
4.34
3.25
2.21
3.06
s.41
13.54
15.64
18.s8
1 9 .3 2
15.34
r3.55
8.45
5.81
4.90
3.ga
4.14
6.9I
L 7. 8 4
l8 .78
25.77
35.46
2s.65
L ?. 1 7
rs.28
8.53
5.94
4.69
5 .3 6
L5.23
1.25
3.Or
5.09
1.40
2.36
L.6g
1 . 4I
S.83
0.26
g.s4
g.r I
0.10
16.59
rs.77
t5.68
29.06
r8. 24
15.5?
8. 8 7
7.75
s.58
4.65
5.25
1 s .l 3
N
1.6I
1.75
I.53
2.56
1.46
f.23
9.93
0.99
L.02
5.79
1.22
I .21
g. 4 4
9.39
s.32
s.53
o. 4 3
s. 4 2
s.37
g. 4 4
s.6s
s.73
0.84
g.6g
1.79
2.s4
2.88
1.71
1.50
1.39
1.21
s.92
9.52
o.s8
9.28
s . 81
2.59
3.98
3.66
2.58
2.34
2.59
1.98
1.46
1.12
0.44
g.4l
I.12
4.44
5.35
5.86
5.66
4.24
3.89
2.76
2.66
2.I0
r.72
2.49
2.44
5.82
6.82
7.14
7.31
5.58
4.54
4.12
2.98
3.r9
2.24
3.36
4.rg
8.73
g.s5
8. 3 4
11.23
7.58
5.53
4.42
4.15
4.55
2.63
A.7S
5.58
7.31
L.42
7.04
1.01
6.24
2.L0
S.58 15.65
6.96
l.S2
4.94
0.59
3.94
0.48
3.87
5.28
4.33
0.22
S.OS 2.63
4.58
s.12
5.23
0.3s
4.35
4.66
3.95
6.55
4.28
3.51
2 . 74
2.53
2.78
r.60
2.15
3.52
s. 4 5
s.35
s.26
s. 4 9
s.39
9.34
s.33
s. 4 4
9.52
s.69
0.73
9.64
3.99
7. 3 2
9.48
5.97
5.24
5.43
4.95
2.8s
I .96
s.L6
r.98
r.14
7.96 TI.42
9 . 5 2 76.95
tt.2g
18.36
7.73 16.95
7.67 l3 .65
8 . 1 2 L2.gg
6 . 5 2 tg.08
7.84
4.14
6.98
3.29
3.46
I.s7
4.6s
1.43
7.62
3.96
16.68
19.51
t9.32
22.5s
r6.68
15.35
L2.58
9.58
9.44
4.24
6.60
2.56
3.69
6.64
3.56
3.94
2.4r
2.44
t.22
s.49
a.0g
o.L2
0.28
18.51
18.46
rg.8s
29.57
22.15
22.64
33.35
22.L6
t7.43
L3.75
12.29
12.99
6.78
7.75
16.7I
1.33
1. 4 8
1.44
1.14
g.x
o.89
0.88
I.25
9.75
s.73
o.9r
0.8r
9.83
S.6S
S.5s
9.49
9.54
9.54
5.63
5.69
9.52
0.96
9.95
0.74
s.r9
s.68
r .02
s.85
s.70
0.52
0.42
0.58
9.5L
s.s5
o.s8
0.r5
2.47
3.54
4.19
3.14
2.34
2.14
2.52
2.46
I . 74
1.18
1.36
1.56
4.OS
3.98
4.82
3.88
3.94
2.79
2.48
3.88
2.42
r.63
2.r7
2.37
5.S8
8.32
5.64
a.9s
4.65
4.25
3.82
5.09
3.89
3.72
3.79
2.89
S.06
0.29
0.68
s.31
s.42
g.t4
0.13
S.41
S.3S
0.Sg
9.s0
g.gS
5.S8
8.S3
4.96
4.59
4.23
4.1r
3.79
4.68
3.59
3.72
3.79
2.89
SDev
cv
9.62
l.7S
I .68
1.46
1.10
L.SO
5.69
9.84
9.88
0.24
s.28
0.42
B-37
16.ss
35.29
18.22
L5.92
11.26
rt.s7
1l .60
6.78
7. 6 3
16.43
(wASHTNGTON)
Percentiles
llo
llean
lled i an
1767
Oct
Nov
Dec
Jan
Feb
lla r
APT
lta y
Jun
Jul
Au9
COULEEDAfi 1 SW
0.74
0.19
s.73
1.28
I.28
0.82
r.43
t.42
0.7r
1.11
L.S8
0.59
s.89
s.9s
0.68
s.79
1.16
9.88
9.46
0.5s
0.55
9.6s
0.68
0.76
s.88
5.22
0.29
9.44
SDev
cv
Lg
25
75
9g
9.98
9.64
g.5s
s.53
o.lg
g.3s
o.52
0.38
g.LA
5.ls
g.r0
9.20
0.16
g.g2
s.00
0.23
g.7s
0.86
9.66
s.34
s.34
g.3g
s.48
s.40
L.64
I .67
I .78
I .5s
l.1S
0.96
I.rg
L.7S
l. t8
s.72
r.04
s.84
r.85
2.92
2.49
I .89
1.52
r.28
1. 6 6
2.26
r.69
I .46
1.32
r.36
2.95
3.95
3.29
2.52
3.58
1.85
2.3r
5.52
3.26
2.33
1.75
I .5I
19.61
2s.68
25.83
26.48
2r.30
12.54
14.95
5.t2
6.52
3.77
3.86
IO.75
1.21
2.25
5.s2
1.82
r.8s
1. 0 8
5.68
0.31
0.2s
S.gS
5.14
S.2S
t8.4s
1.8.43
2s.8r
24.57
7 9. 5 5
1r.45
13.37
4.81
6.32
3.77
3.72
10.55
19.16
24.24
25.28
25.79
22.25
18.58
13.48
9.57
6.28
5.25
4.94
9.50
29.79
31.s6
31.61
47.7A
28.84
24.58
r5.34
r3.40
8.89
7.99
9.57
12.24
2.s8
2.9I
6.62
2.31
4.95
3.62
1.54
5.9s
g.t7
0.oI
9.20
9.24
27.7t
28.15
24.99
3 9 .3 9
23.89
2 0, 9 6
13.80
t2.50
8.72
7. 9 8
9.37
12,gg
7.38
L2.49
It.97
13.52
8.71
5.52
3.10
2.32
2.73
9.94
I5.23
13.57
14.07
22.9?
12.72
7.89
3.75
5.95
2.54
1.71
2.79
3.4s
9.27
I.2r
2.59
I.6S
0.50
g.2g
0.14
9.7s
9.04
g.ss
S.9S
A.s4
9.95
r2.36
11.48
2r.3'7
12.22
7. 6 5
3.62
5.85
2.50
1.71
2.'t9
3.41
2157
DIABLO DAT.I
Oct
8.14
7.83
Nov 11.12 L9.26
Dec 12.78 12.76
Jan IS.97 Ig .82
Feb
8.48
8.Sg
f,lar 6.84
6.27
Apr
4.52
3.90
l,!ay 2.68
2.86
Jun
2.AI
1.98
Jul
1.38
1.39
Aug
7.75
1.52
Sep
3.89
3.52
4.28 s.53
A.75 9.43
3.87 s . 3 9
5 . ?6 0 . 5 3
4.7I 0.56
2.97 o.43
2.55 0.56
g.47
I.26
1.11 0.55
9.83 0.69
1.lg g.6s
2.59 0.67
3.49
5.S8
8. 6 6
4.50
3.s8
3.31
2.92
9.78
9.69
s.31
0.38
0.8s
5.SI
?.38
9.91
6.L2
4.44
4.54
2.88
r .63
1.46
9.64
0.82
I .68
11.s3
14.42
15.34
t3.80
tt.7s
9.39
6.19
3.44
2.6L
r.94
2.6t
5.51
13.77
17.96
I7.56
18.22
13.42
r9.76
7.24
4.42
3. 0 1
2.30
3.28
7.44
29t4
O ct
Nov
Dec
Jan
Feb
f ' af r
Apr
itay
Jun
Jul
Aug
Sep
5.98
6.59
5.68
7.56
5 . 74
4.68
3.66
3.02
2.14
I .94
2.57
3.Ls
5.52
0. 4 3
s.3s
0.45
g. 4 0
9.37
S. 4 5
0.60
9.69
s.81
0.78
s.60
3.80
7.79
6.43 11.98
11.18 r4.54
7 . 8 6 1 1. 5 0
7.63
9.46
6.46
9.26
3.18
5.36
r.84
3.53
s.77
1.54
9.38
9.76
9.43
9.76
1.94
2.71
r4.12
2g.Ig
22.48
2 S. 9 2
18.30
15.28
L5.84
6.19
4.39
3.4s
3.96
7.63
LAKE WENATCHEE
3.63
3.15
2.55
6.46
5.98
3;38
7.98
7.97
2.79
7.54
6.89
4;59
4.98
t.5t
2.65
3.12
2.76
1.63
1.65
I.5S
9.99
I.23
5.99
t.g3
I.03
0.92
9.69
9.45
S.4g
O.39
g.?O
5.76
5.66
1.31
1.28
O.9g
s.69
0.52
s.35
s.6t
s.53
9.52
s.6s
s.84
s.67
9.87
s.92
0.68
s.87
2.24
4.24
2.55
2.53
1.32
0.48
s.26
0.20
s.02
9.02
5.06
4446
ocr
Nov
Dec
Jan
Feb
llar
Apr
ilay
Jun
Jul
Aug
sep
F O R K SI E
LI . 4'7 I0 .28
15.56 15.48
L8.77 19.54
f6.93 16.80
1 4. 3 3 1 3 . 1 6
1 2. 5 7 L 2 . 9 6
8. 14
8. 98
5.56
4.59
3.I2
2.96
2.4I
2.IS
2.67
2.96
5.17
3.83
t . 74
4.66
3.85
8.42
5 . 9 5 lo.g8
3 . 79 r s . 2 9
2.97
6.46
2 . O g 4 .I 8
s.8s
2.49
6.52
1.49
s.42
r.60
0.13
9.66
0.L6
r.sz
9.57
1. 7 8
B- 38
0.og
s.13
g.2s
s.25
0.s3
s.s4
o.o3
s.L5
o,05
Bange
0.ss
o.s4
o.96
0.14
seP
l,lih
2.95
3.82
3.00
2.27
3.55
1. 8 1
2.28
5.37
3.21
2.33
l.7s
I.5I
s.7s 9.78
9.47 0.69
S.58 0.73
r.s5 o.9t
S. 6 4 a . 7 3
5.58 I.27
s.56 1.02
0.47 s.86
o.s6
Itlax
t.62
2 . 7g
g.gg
g.gg
(t{ASHTNGTON)
Percentiles
Mo
t{ean
4549
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
JuI
Aug
Sep
LAURIER
I.50
I.42
1.93
I.92
2.3I
2.2A
2.95
2.14
I .48
1.32
1.2'l
1.28
I.39
I.32
1.89
1.58
2.94
1. 8 8
I .12
l.O4
I . 31
I.SG
l.SB
5.68
5128
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
sep
} I A Z A M A6 S E
I . 38
9.99
2.93
2.82
3.54
3.28
3.15
2.87
2.28
2.25
1. 2 8
I.2g
g.92
A.78
5.98
5.66
l. S5
S.7S
g.41
5.53
0.82
5.36
g.6g
0.72
5613
i ' t O S E SL A K E 3
Oct
S. 8 9
9.58
Nov
I .21
t.0S
Dec
I.29
I. t6
g.92
Jan
5.82
Feb
5.78
9.69
llar
5.62
9.66
Apr
5.56
9.52
May 9.73
S.6S
Jun
9.69
9.66
Jul
9.32
O.16
Aug
0.33
0.18
g.2S
Sep
0.38
58S1
Ocr
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
J ul
Aug
Sep
cv
Tg
25
75
9g
I. 14
0.89
5.82
O.8S
0.76
A.54
S.8l
I.96
1.97
5.15
1.17
0.88
a.75
s.46
s.36
s.39
0.5r
0. 4 3
0.58
a.56
s.53
s.66
0.22
s.79
t.2s
t.s9
9.56
s.42
s.42
s.78
9.78
o.13
0.t5
9.22
s.66
L.26
I .76
r.33
s.9s
r.63
s.72
I .08
1.18
s.58
s.36
g. 4 2
L.77
2.45
2.94
2.55
L.97
I .68
1.84
2.42
2.64
t.62
2.58
1.84
3 . 95
2. 8 8
3.42
3.A6
2.7I
1.83
2 . 74
3. 4 5
3.39
1.21
1.69
1.6I
2.50
7.22
0.99
9.77
S.9S
S.9S
9.53
S.9S
5.67
9.87
s.58
s.46
0.63
9.53
0.79
9.84
9.92
s.85
0.99
9.26
g.7s
1.65
0.77
0.73
9.28
s.I3
g.2r
0.r4
a.o2
g.ga
s.g4
5.54
r.82
2.38
1.69
1.55
5.64
5.26
s.44
0.42
s.69
s.11
s.t8
s.88
s.6I
a.74
0.83
s.76
1.38
1.15
L.25
g.g8
s.18
0.37
s.38
g.I2
s.L3
s.s8
0.08
s.96
s.0g
s.gs
s.g2
0. 4 8
5.45
5.28
s.42
s.43
5.37
s.44
S.53
s.64
0.80
5.73
g.s7
5.77
6.12
9.86
7.78
5.72
4.79
3.97
1.63
o.72
0.54
9.49
t.77
lttedlan SDev
NEAH BAY I
70.42
9.93
I4.AA
13.88
16.5I
f6.98
14..39 14.66
12.51 11.14
IS.Li
IS.SB
7.I7
7.53
3.95
3.64
2.86
2.56
2 . 42
2;.$5
2.52
2.39
4.42
3.78
E
S.Ag
I.29
t. 17
S.55
S.6g
9.38
5.42
g.6g
5.53
5.44
S.3g
g.48
E
4.99
6.37
4.65
6.s8
s.I9
3.71
3.12
2.59
1.83
1.93
1.85
2.59
g.9g
9.82
r.ls
9.93
r.g0
I.0'l
g.9t
g.69
I{ax
ltli n
Range
2. 9 1
2.27
4;81 S.97
4.83 0.37
4.26 0.94
3 . 82 0 . 2 8
3.21 S.34
2.57 9.11
3.18 g.2L
4.59 5.52
4.6s g.41
2 . 7 6 g. 0 5
4.45 g.Ss
3.s6 s.06
4.74
4.46
3.32
3.s4
2.87
2.46
2.97
4.s7
4.24
2 . 7r
4.48
3.5s
2.rg
3.63
4.54
4.57
3. 0 8
I .89
1.35
r.30
1.52
g.7s
1.38
1.15
2.89
5.86
5.84
5.59
3.55
2.4r
2.t6
r.76
2.35
r.42
2.2s
I.56
5.56
6.95
7.56
8.39
5.93
4.l9
2.62
4.93
3.7s
2.2I
3.78
2 . 74
S.L5
0.r5
0.88
9.43
5.48
0.12
S.Ss
9.02
0.gr
S.0S
0.SS
S.SS
s.41
6.75
6.68
7. 9 6
5.45
4.s7
2.62
4.91
3.69
2.2I
3.78
2 . 74
s.24
s.4t
9.65
0.52
5.40
9.27
9.28
s.26
s.28
0.sI
s.s4
g.o8
1.l5
r .60
I.62
L.24
s.98
0.88
s.78
s.98
s.97
0.38
s.52
g; 5 2
I.98
2.94
2.tA
t.74
I.3s
I .14
I.S8
1.56
I .38
s.8I
5.92
I.98
3.71
7. 8 2
7.t9
2.56
4.lt
r.42
1.85
2.79
2.59
2.24
r.35
2.97
S.SI
S.SS
s.s8
g.g4
g.s3
g.s2
g.so
0. s s
9.02
S.Sg
g.os
g.sg
3. 1 9
7.82
? .r l
2.52
4. 9 8
I .4s
r.85
2.79
2.57
2.24
1.35
2.97
7. 1 6
9.28
l4.St
9.78
7. 7 6
6.92
5.58
2.44
1.66
5.96
L.OS
2.32
12.35
I?.52
I9.68
I7. 33
I5.89
I3 .41
9.56
5.1s
3 . 94
3.49
3.49
6.57
L6.96
22.44
2I.99
22.s5
L9.25
1 5. 3 9
1r.30
7.35
4.82
5.6s
5.04
7. 6 0
24.93
29.84
2 5. 8 8
35.45
26.9s
r5.34
t4 .92
9.59
7. 8 3
7. 6 s
8.ls
rs.33
B- 39
z. zt
2.16
4.29
5 . 85
2.89
4 . 74
3.91
s.78
S.5s
5.33
s.ss
0.ts
s . 74
22.77
2 5 .s s
2 g. s 3
27.56
22.16
12,43
I 3.24
8.59
7. 5 5
7. 6 s
8.ss
9.59
(l{ASHINGTON)
Percent i Ies
Itlo
llean
6114
Oct
Nov
Dec
Jan
Feb
lfar
Apr
ilay
Jun
Jul
Aug
sep
O L Y I , I P I AW S OA P
4.75
4.60
2.42
?.42
7.{1
3.46
8. l8
8.54
3.97
7.48
7.56
4.94
2.77
5.82
5.18
4 . 74
4.32
2.22
2.94
2.84
1.32
r.93
1.52
L.2S
L.4g
L.25
5.94
0.81
9.66
5.69
g.8S
I.24
I.27
L.60
2.33
2.22
6624
Oct
Nov
Dec
Jan
Feb
Uar
Apr
f'tay
Jun
Jul
Aug
Sep
P O R TANGELES
2.47
2.12
1.55
3.?6
3.48
L.76
4.53
4.Or
1.46
3.95
3.66
2.2s
2.93
2.44
1. 5 4
2.SB
r.82
1.10
1.22
I.22
0.65
9.92
9.94
5.46
0.82
s.7s
0.55
5.49
o.49
5.36
5.79
0.56
5.76
1. 19
1. 1 4
S. 7 9
lled i an
SDev
cv
LS
25
s.5r
o. 4 7
s.38
L.67
2.72
3.76
2.84
2.79
4.49
5.85
| .1r
2.46
L.22
s.66
s.24
0.94
s.l2
s.4t
6.rs
0.78
1. 4 7
1.99
t.26
1.11
s.74
9.42
0.3r
o.19
g.s6
I.5S
2 . 74
3.35
2.29
1.78
1.38
0.82
s.64
s.36
0.2s
9.53
0.48
o. 4 7
s.45
s.62
9.67
s.85
s.98
s.69
s.63
g. 4 7
9.36
0.5r
9.52
0.53
9.49
s.49
6.68
s.73
0.97
A;67
3.r0
75
9S
llax
f{i tr
Rang e
9.78
1.37
2.56
9.69
1.71
s.48
o.37
9.25
g.g5
o.sg
g.ot
s.gs
9.35
14.14
L2.26
19.rs
11.47
9.65
5.55
5.58
4.s4
2.68
5.44
7. 5 9
3.7r
6.s4
9.86
to.3s
5. 14
7.44
8.79
L2.26
L2.24
L2.32
t0.58
3.LO
1.99
1.31
0.72
9.26
0.52
L.29
4.LO
2.66
I .82
t.3a
L.60
2.94
4.64
3.30
2.60
l.5s
3.s8
4.7s
L9.08
15.5r
14.32
19.84
r3.18
10.13
5.87
5.83
4.s9
2.68
5.45
7.59
4,48
6.20
5 . 93
7. S g
4.70
3.73
2.t8
1.41
1.58
L.g4
t.7s
2.39
7. 7 5
8.44
7.7s
r1.06
6.97
4.64
2.79
2.49
2.4s
1.56
3.67
3.s8
7.29
5.46
s.6s
7. 8 4
I.27
6.43
s.90 10.16
0.83
6.14
0.54
4.rS
g.g9
2.6r
S.tS
2.39
g.g9
2.3I
g.gs
1.56
S.OO 3.67
0.94
3.54
?.8s
s.s7
,s.26
s.2g
9.45
3.14
5 .s 8
2.66
5.12
4.23
2.75
r .49
1.17
r.14
s.68
1.18
I.90
RAINIEROHANAPECOSH
6896
oct
6.99
6.00
3.86 0.55
Nov 1I.55 I5.87
5.14 5.44
Dec I3.48 13.75
5.18 9.38
Jan 13.01 I9.84
7.65 9.58
Feb
4.13 9.45
9.2I
8.51
Mar
7.13
6.69
3.11 9.44
Apr
4.49
4.25
2.97 9.46
ltay
2.50
2.94
1.53 4.52
Jun
1 . t B '05..5812
2.28
2.28
Jul
S.8g
5.76
0.94
Aug
I.67
1.22
1.52 S.9I
Sep
2.84
2 . 3 8 g . 74
3.24
1.34
4.86
5.98
4.48
4.s8
3.39
1.91
L.06
0.92
o.s6
s.24
s.68
4.98
6.82
9.88
6.56
6.39
4.64
3.06
1.96
1. 5 0
0.37
5.46
r.6S
8.20
L4.76
r7.3r
19.s6
11.3r
9.36
5.74
4.14
2 . 72
1. 4 8
2.3L
4.29
12.77
r7.75
2r.gg
22.77
15.9s
1r.14
7.19
4.82
3. 9 0
2.16
4.32
6.55
1 6. 0 9
25.69
23.5s
3r.59
r8.s3
14.25
9.82
7. s 9
5.41
2.60
5.66
L5.95
l. 18
L.22
4.43
2.35
1.93
I .23
5.69
0.35
9.64
S.gS
g.gs
9.11
R I M R O C K( T I E T O N D A M )
2.SB
I.96
1.53 0.74
4.93
3.48
2.39 9.59
4.89
{.56
2.67 0.55
4.41
4.26
3.gA 0.68
2.89
2.47
1.80 5.62
2.07
I.88
I.24
S.6g
1.23
I.26
9.85 0.69
g.66
g. 7 3 0 . 83
9.88
g . 7 1 9 . 83
0.85
0.62
9.39
0.28
9.44 1.11
9.7A
0.48
O.78 I.12
s.69
0.63
O.69 5.87
s.36
t. l5
1 . 73
r .08
r.go
s.52
9.21
9.16
0.20
g.so
g.s0
s.g4
s.96
2.27
2.92
I .52
I.50
L.20
0.48
5.32
s.33
s.07
0.08
0.14
2.88
5.82
6.08
6.54
4.12
2.95
r.73
r.26
L.22
s.46
9.82
t.94
4.63
7. 6 4
8.96
8.56
5.08
3. 9 6
2.45
r.9?
1.83
9.98
I.'92
r.4S
6.52
9.75
12.s3
11.98
7.65
5.28
3.38
3.56
3.11
1.76
3,07
2.36
9.15
5.87
5.59
9.16
Ll . 12
s .9r
5 . 2 2 1'1l . 7 6
.39
5.26
5.08
S.2g
3.32
S.s6
3 .s 4
0.02
3.11
A.ss
L.76
S.g0
3.s7
0.so
2.36
0.ss
7038
oct
Nov
Dec
Jan
Feb
l|ar
Apr
tlay
Jun
Jul
Aug
seP
B- 40
1 4. 9 I
24.47
L9.07
29.24
L6.65
L3.02
9.r3
6 . 74
4.77
2.65
5.66
I9.84
(wASHTNGTON)
Percentiles
l'led i an
SDev
cv
LO
25
75
90
1.12
r.24
0.99
L.2g
1. 1 S
0.77
9.75
0.4r
5.5'7
A.56
O. 6 5
5.50
g.7g
0.55
g.61
0.89
s.49
r.s5
5.82
0.89
s.30
0.52
1.12
s.74
0.46
9.76
0.32
0.67
s.56
o.0g
s.s4
o.2L
0.72
1.41
1.63
L.26
r.Sg
0.93
s.74
0.84
5.89
o.l2
0.26
A.34
2.r8
2.74
3.s4
2.84
2.r4
l .87
L.79
1.98
L.92
s.66
r .10
1. 3 5
3.08
3.69
4.18
3. 8 s
3.25
2.68
2.55
2.77
2.44
1.34
I . 75
2.50
2.18
3.99
4,26
3.41
2.36
2.32
1.99
4.09
6.48
6.?8
6.26
5.36
4.46
2.9r
a.68
9.28
0. 3 2
1.13
2.t8
I .S8
1.34
2.32
5.99
7.89
8.47
7.86
6.41
5.54
3.49
2.99
2.86
2.94
2.59
3. 7 8
s.48
s.6r
s.52
g. 4 4
0.56
s.5'l
s.76
L.27
L.20
9.77
9.46
s.54
s.82
0.84
0.54
s.72
s.38
0.46
9.30
s.gg
0.os
0.s7
s.66
l.2g
1. 3 6
r.l2
0.86
5.89
5.87
5.68
9.42
g.gr
g.g6
0.25
r .92
2.49
2.66
2.39
1. 7 9
1.66
2.53
1.97
r.24
0.58
s.94
r.3s
1.05
g.7r
9.76
a.63
0.81
s.91
0.94
0.99
t.sg
L.2T
r.37
s.95
g.s6
a.rs
o.14
o.4s
s.s8
a.t2
0.92
s.06
s.s2
o.sa
o.gs
a.gs
9.13
0.47
0.5L
9.59
9.33
0.22
s.07
g.14
0.18
g.sl
g.sr
g.s4
s.82
L.26
1. 4 6
r.74
1.14
0.89
9.82
9.74
1.15
s.26
s.42
0.62
Mo
ilean
7I8O
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
ROSALIA
1.14
1.49
2. 18
2.Sg
2.32
2.49
I .99
2.L6
I.42
I.7g
1.38
1.53
I.22
I.33
1.55
1.12
1.29
I.42
S.4I
9.52
9.74
9.54
9.77
I.0S
7478
oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
sep
S E A T T L E - U N I V .O F T J A S H I N G T O N
1.66
1.65 6.59
3.3s
2.95
2.29
2.56 O.4S
5.L2
5.22
2.LS
4.82
2.28 0.42
5.45
2.gS
4.92
2.I5 5.44
5.12
1.89
1.71 5.43
3.98
3.93
I.52
I.59 9.46
3.18
3.46
I.29
2.40
2.39
S.8I 0.34
S. 6 5
I.SS 5.59
1. 7 1
I.45
g.44
1.49
I.2S
O. 9 3 9 . 6 2
g.g9
g.8g g.9L
0.88
9.65
0.L2
S. 9 ' 7 0 . 6 9
9.89 5.92
1.3S 9.69
0.27
1. 8 9
I .54
8931
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
JUI
Aug
Sep
W A L L AW A L L AW S OC I
1.41
1.36
9.92
1. 8 6
I.92
S. 9 4
2.I2
2.gg
1.01
l.2I
1.98
1.66
I.47
1.58
9.77
I.40
1.35
0.62
1.44
1.33
0.81
l.S9
1.49
1.14
1.06
O.8g
0.87
g.l4
S.38
9.48
9.68
9.56
5.35
9.85
5.76
9.66
9465
Oct
Nov
Dec
Jan
Feb
Mar
APr
May
Jun
JUI
Aug
Sep
Y A K I I , I AW S OA P
O.54
9.5'l
9.28
5.99
S.7I
5.96
I . 18
I.S7
O.9O
I.31
1.26
5.83
0.81
0.76
9.66
S.6S
0.47
9.54
S.5S
9.41
9.42
S.5S
0.56
5.45
g.64
9.38
0.64
g-SB
S.L9
S.16
9.32
6.20
.544
9.34
t.24
5.32
o.8r s.6L
r.17 9.76
9.65
s.5r
r.s3
B-4I
2.rs
Uax
irin
4.42 0.92
5.63 9.38
4.49 s.78
5.37 9.44
5.37 0.31
3.14 9.34
3.2r g.L7
6.22 g.r2
3.r0 s.39
2.26 o.sg
2.37 0.gs
3. 5 2 s . g g
REnge
4.45
5.25
3 . 7r
4.93
5.06
3.45
3.04
6.r0
2.71
2.26
2.37
3.52
7.50
9.13
rs.56
9.83
7.62
7.s6
4.58
4.72
3. 5 8
3.77
4.gg
s.49
s.54
s.55
1.15
0.89
1.58
0.43
0.59
0.39
s.33
s.oa
6.96
8.58
9.4r
8.94
6.54
5.63
3.99
4.33
3.25
3.'17
2.86
3.92
3.75
3.91
2.34
2.37
2.46
3.48
2.5'1
l.1S
r.36
1.86
4.25
4.13
4.31
5.86
3. 9 9
2.94
3.26
4.19
3.s4
1.78
2.94
2.4I
g.s3
9.11
0.29
0.34
g. r 7
9.34
9.rl
0. 2 3
o.99
s.gs
s.sg
0.90
4.L7
4.52
4.92
5.52
3.82
2.65
3.15
3.96
2.95
1.78
2.94
2.41
r.47
1.84
2.25
2.38
1.5S
I .le
1.25
r.s2
r .67
0.44
5.62
g.8A
2.22
2.85
4. 19
3.66
3.11
2.63
t.62
2.76
2.rg
g.7r
2.rg
0.98
s.os
g.sg
g.s7
0.r3
2,22
2.86
4.12
3.53
g.gs
s.s3
a.ss
5.46
s,ss
o. 0 r
0.sg
s.93
3.r1
2.62
r.62
2. 1 3
g.gs
s.gs
s.sg
g.7r
2.r0
s.98
g.gg
2.99
APPENDIX C
SKET{NESS STA,TISTIC
SEASONAL AND ANNUAL PRSCIPI'TAT TOL{ MONTHLY PRECIPITATION DATA - 43
c-t
244 STATIONS
STATIONS
S E A S O N A L S K E h I N E S S( L 9 4 6 - L 9 7 9 )
( oREGoN)
Station
I.D.
aL97
a265
6394
A3TB
g32B
a356
a4r2
a4r7
a 4 7L
a694
a723
a897
Lg55
LL76
L2A7
I 433
r546
L552
I 57r
L643
L 76 5
LA62
L897
r9g2
L926
L946
2LI2
2l-35
2L6B
2277
2496
2449
2633
2672
2693
2769
28A5
2997
3995
3121
3356
3492
3445
3542
Name
Antelope
Arl ington
Ashland
Station
Astor
Experiment
WSO AP
Astoria
Austin
3 S
BaKeT FAA AP
Baker KBKR
Bandon 2 NNE
Bend
BeuIah
Bonneville
Dam
Brookings
Burns WSO CI
Butte Falls
I SE
Cascadia
Chemult
Cherry Grove 2 S
Chiloquin
I E
Clatskanie
3 W
Condon
CorvalIis-State
Univ.
Cottage
Grove I S
Cottage
Grove Dam
Cove
Crater
Lake NPS HO
Dal I as
Danner
Dayville
Detroit
Drain
Dufur
Elkton
3 SW
Enterprise
Estacada 2 SE
Eugene WSO AP
FaIIs
City
2
Forest
Grove
Fremont
Friend
GoId Beach Ranger Station
Camp
Government
Grants Pass
GrLzzLy
c-3
Winter
Sumrner
-9.28
-a.97
-9.2L
-9.L7
q.a9
a.a8
9.23
4.24
6.3A
-9.a4
g.L2
-9.19
-9.29
-a.79
-4.43
4.22
-g.gL
g.15
-9.22
-a.a8
a.g2
4.23
a.64
-9.a5
-4.42
-9.39
-a.a4
-a.oB
-a.46
a.3a
-9.93
a.2L
9.25
-g.gr
-9.44
g.g9
g.7B
-s.24
-9.29
a.36
a.12
-9.43
b.19
q.12
-9.45
a.2a
a.37
o.5L
a.43
a.43
a.63
L.L2
a.63
r .18
6.46
a.3L
9.43
a.24
a.36
a.97
a.72
6.65
a.Ba
g.8a
a.49
L.AL
a.35
g.5L
a.68
6.96
a.75
-a .37
1 .1 6
9.64
a.3a
g.a8
b.55
-9.23
a.26
6.7L
a.L8
r.62
9.55
g.L4
@.58
o.22
9.25
a.45
Year
a.aL
g.2a
-9.3L
-9.95
9.24
a.23
a.58
a.86
a.L5
6.22
6.43
a.a3
-a.63
A.LT
g.3a
g.2a
-9.43
a.ar
g.L6
9.27
6.35
g.aa
-g.rL
-a.13
-4.26
a.lL
-A.TL
-a.29
g.6L
a.25
g.aB
a.37
-4.24
g.s6
g.16
s.7a
-s.25
-9.a7
a.73
a.3L
-q.35
a.3r
g.23
a.g5
(onncow)
Station
I.D.
36A4
3692
3779
3827
3447
39A8
4gg3
4A98
4 1 33
4161
429r
44A3
44]-T
4566
4622
4679
4 8 1t
5A8A
5r39
5L6A
51"62
5362
5384
5424
5429
5593
5734
6A32
6 9 73
6L79
62L3
6243
6405
6426
6468
6546
6634
6749
682@
6883
6997
Winter
Name
Halfway
Refuge
Hart Mountain
Headworks,
Portland
Water Bureau
Heppner
Hermiston
2 S
HiI I sboro
Hood River
Experiment
Station
Huntington
Il Iahe
Ione I8 S
John Day
Keno
Kent
KIamaLh Falls
2 SSW
LaGrande
Lakeview
2 NNW
Leaburg
I SW
Lower Hay Creek
Ivladras
Malheur
Branch
Station
Exper:iment
Malheur
Refuge HDQ
Ranger
McKenzie Bridge
Station
McMinnville
Medford Experiment
Station
!ilSO AP
Medford
MiIton
Freewater
l"loro
Newport
Bend FAA AP
North
Nyssa
Fish Hatchery
Oakridge
Ochoco Ranger Station
Owyhee Dam
eaisley
Parkdale
2 SSE
WSO AP
Pendleton
Rock I SE
Pilot
KGW-TV
Portland
Powers
Pr ineville
2 SW
Prospect
c-4
a.58
9.69
4.33
-a.aL
a.86
-6.33
-4.26
Summer
Year
L.A9
a.6q
g.L7
-@.4s
9..73
a.64
9.64
9.77,
g.g8
9.46
r .35
Q.48'
-g.wB
-6.t4
g.a4
-q.56
-9.05
-6.26
-9.95
-9.95
-9.L2
-9.63
-6.29
-9.a3
a.g9
-9.94
-6.A9
-a.a9
s.68
a.63
a.42
-6.25
-a.L7
9.63
g.5r
-6.13
-fr.64
-s.2L
a.7a
a.7L
6.54
-a.a4
a.37
a.L4
-a.L8
-a.a5
-g.rr
9.54
a.94
g.19
L.A5
9.64
a.7L
fl.36
a.86
4.26
@.45
4.23
r .14
g.B7
s.28
-9,88
a.26
-9.53
a.ar
-4.6L
g.a8
9.29
9.97
-a.La
a.2a
-4.t6
-a.59
g.g4
a.a5
g.g6
g.7B
6.88
a.74
I .4I
9.48
a.27
6.22
a.39
a.55
a.75
L.LA
9.23
6.57
-9.o9
-9.49
a.95
-a.14
-o.2L
a.28
6.24
-a.41
a.!.9
a.o3
g.lr
s.Lg
-9.13
g.IT
-a.44
-0. l8
o,ag
fr.19
a.33
L.g6
-a,2r
a.19
a.28
-s.95
A,LL
a,g4
s.g7
(onecou)
Station
I.D.
7A52
7 A82
7 169
7 2AB
725A
733r
7 354
75AA
7 64L
aa29
84A7
4466
8494
8726
8 74 6
878A
8797
8818
8 8 33
B8B4
8997
9664
9316
Name
Redmond 2 W
Reedsport
Riddle
Riverside
Rock Creek
Roseburg
KQEN
Round Grove
Salem VJSOAP
Seaside
Squaw BuLte Experiment
Station
The Dalles
Three Lynx
Tillamoook
1 W
Ukiah
Union Experiment
Station
Unity
vale
FaIIs
Valley
3 SSE
Valsetz
Veronica
2
Wallowa
Wasco
Wickiup
Dam
Winter
Sumrner
-s.a7
a.59
a.34
a.52
4.23
g,4L
a.06
-9.65
g.2L
-9.a3
-g.gL
-9.32
a.g8
9.54
I .18
6.58
6.59
a.ag
Year
a.a9
9.29
4.47
g.r3
-4.93
a.2L
a.35
g.a7
9.44
9.68
a.s6
g.3L
a.gL
-a .45
-9.93
-a.97
-4.22
a.4L
a.44
-9.a6
L.22
a.55
a.68
L.47
9.99
6.74
a.2L
9.65
a .47
4.42
a.23
a.g2
a.48
g.3L
a.aL
-a.46
4.22
-A.AL
a.a5
-4.16
g.u6
a.L9
6.A7
-a.29
a.3L
9.59
a.27
9.26
-9.zfl
-9.r5
-9.a9
a.75
9.94
a.43
a.58
L.AA
a.42
a.33
@.4A
a.4r
-9.25
a.4L
a.ra
a.g3
-g.TL
a.26
-a.95
( wASHTNGToN)
ggaS
ar76
9242
9257
q482
o564
a568
g 72 9
6472
a945
r233
L276
L35g
I 385
r 395
L4L4
L484
L5A4
Aberdeen
Anacortes
Ariel
Dam
ArI ington
BaLtle
Ground
Bellingham
2
Bickleton
Blaine
Bremerton
Buckley
1 NE
Cedar Lake
Central ia
Chelan
Chesaw
4 NNW
Chewelah
Chimacum 4 S
Clearbrook
CIe EIum
g.ra
a.6L
9.62
-9.25
9.42
9.57
c-5
@.65
@.39
a.52
s.88
9.53
s.33
a.gL
9.44
2.62
a.82
a.aL
a.59
9.58
2.BB
a.Lg
a.a6
a.46
9.98
g.14
4.22
g.8a
g.LL
@.26
6.94
4.22
-fr.25
@.32
6.39
9.34
g.g2
6.44
a.72
(wassrmcroN)
Station
I.D.
15 8 6
L65g
L666
L679
176A
L767
I 783
l-934
I 958
r992
2ga7
2A3g
2L57
25A5
253L
2675
29L4
3222
3284
33 5 7
35A2
3529
3546
3975
4677
4A84
4L54
42Ar
4338
4394
44A6
44L4
4446
4486
4549
457 2
4679
4769
497 L
5r28
5224
5425
5525
56 1 3
56 5 9
5688
57fr4
Name
Co"l-fax I NW
CoIviIIe
AP
Conconully
Concrete
Cougar 6 E
Coulee Dam I SW
Coupeville
I S
Cushman Dam
Dallesport
FAA AP
Darrington
Ranger Station
Davenport
Dayton I WSW
Diablo
Dam
Ellensburg
Elma
Everett
Forks
I E
Goldendale
Grapeview
3 SW
Greenwater
Harrington
5 S
Hartline
Hatt'on
9 ESE
Irene Mt. Wauco.nda
Kahlotus
5 SSW
Kalama FaIIs
Hatchery
Kennewick
Kid Val-Iey
La Crosse
Lake CIe EIum
Lake Kachess
Lake Keechelus
Lake Wenatchee
Landsburg
Laurier
Leavenworth
3 S
Lind
3 NE
tongview
Mansfield
Mazama 6 SE
McMiIIin
Reservoir
Mineral
Monroe
Moses Lake 3 E
Mt. Adams Ranger Station
Moxee City
Lq E
Dam
lrlud Mountain
C*6
Winter
Summer
Year
-4.4L
L.45
a.85
2.AA
-a.a4
s.6a
-6.A9
9.27
fr.28
-g.La
a.L8
-9.58
r.52
g.L4
-a.52
-6.28
a.37
6.6L
-4.42
g.gL
a.3L
-9.25
-6.35
a.aa
9.37
9.28
4.23
9.33
a.38
a.46
9.82
-a.a5
g.g6
g.L4
-a.a9
g.a9
-g.gL
-4.23
a.25
4.64
9.45
-s.60
-9.42
9.37
-4.2L
-a.38
g.aB
g.68
-9.16
a.63
g.qL
a.5r
6.50
3.42
a.78
9.73
L.26
a.44
2.67
I .34
9.69
2.38
9.83
r.aa
a.59
a.88
r.2g
a.65
3.27
2.89
r.72
L.L2
a.96
a.54
L.43
a.38
r.7a
r.@8
a.97
9.76
r.26
s.46
r .19
2.24
3.13
9.86
3.14
2.43
g.17
6.94
g.37
L.29
9.52
a.64
a.L5
g-.'43
A;75
6.5L
a.53
I .13
9.35
-9.53
L.45
a.24
9.76
-a.a6
g.5g
a.g8
a.29
s.87
o.38
-9.a8
-a.23
9.28
I .86
r.g6
I.17
a.4g
a.5r
g.7L
I .19
a.27
a.5L
9.29
a.s7
a.3L
a.aL
a.16
a.4L
a.79
2.23
-9.16
L.25
9,62
-9.16
-a.28
4.42
A
- 9 ." r678
Q.33
9.25
(WASHINGToN)
Station
I.D.
58sL
5832
584s
5844
5946
6939
6696
6I14
6r23
6295
6553
66LA
6624
6678
6768
6789
6893
6846
68BA
6896
6969
6 9 74
7 s38
7 959
7LgA
7473
7 478
75A7
7s38
7 584
7773
7 938
7956
7 987
8634
8A59
82q7
8286
8348
8 7 73
893r
8959
9gL2
9g58
9474
9238
9327
9342
9376
9465
Winter
Name
Neah Bay 1 E
Nespelem 2 S
Newhalem
Newport
Northport
Odessa
OIga 2 SE
Olympia
WSO AP
Gnak 2 NW
Palmer 3 ESE
Pleasant
View
Pomeroy
Port Angeles
Port
Townsend
Prosser 4 NE
Pullman
2 NW
Puyallup
Experiment
Station
2 SW
Quilcene
Quincy I S
Rainier
Ohanapecosh
Randle I E
Republic
(Tieton
Rimrock
Dam)
Ritzville
I SSE
RosaI ia
Seattle-Tacoma
WSO Ap
Seattle-Univ.
of Wash.
Sedro Wooley
Sequim
Shelton
Snoqualmie FaIls
Spokane WSO AP
Sprague
Spruce
Startup
I E
Stehekin
4 NW
Sunnyside
Tacoma City
HaII
Tekoa
Vancouver
4 NNE
Walla WalIa WSO Cl
Wapato
Watervil Ie
loleI lpin it
Wenatchee
Wilbur
Wilson Creek
Wind River
Winthrop
1 WSW
Yakima WSO AP
c-7
a.3s
6.A6
@.19
-a.L9
9.28
.g.TL
g.gL
-a.96
@.3A
-a.L5
g.L7
-4.25
-9.L3
g.s9
a.29
-a.aL
-9.r3
-o.L2
6.47
-4.L2
-a.47
a.7B
-a.66
-a.35
-a.L3
-9.46
-9.6L
g.L4
-s.4@
-9.22
-g.rq
-9.22
-9.42
a.L6
-a.a5
a.2a
2.53
-a.38
-g .45
-a.L4
-g.aL
9.54
-fl.L5
fr.13
-9.33
-9.s8
9.32
-9.22
-9.17
s.64
Summer
Year
L.A3
2.94
a.52
9.95
a.65
2.25
g.9L
r .14
2.A4
a.4g
r .13
t.76
a.66
L.A2
6.64
r.g6
a.59
9.32
r .33
9.48
-4.59
9.22
a.74
a.g8
g.a6
9.96
a.35
9.42
6.48
a.a2
a.3r
a.36
4.26
-a.r7
9.47
L.74
a.37
9.26
I .56
-@.LL
9.44
g.14
3.36
t.32
a.63
-4.22
r .86
r .54
9.74
6.78
a.68
r .19
L.28
9.28
I .38
r.8a
a.52
-a.aL
r.52
a.54
L.gL
I.r8
g.7B
L.29
L.A5
2.89
L.29
r.95
2.56
2.79
a.74
r.75
r.63
-g.ra
9.36
s.a9
-9.12
a.52
g.ra
-9.a5
g.L5
a.6L
a.53
a.16
4.46
s.29
L.79
-9.a7
a.52
a.L5
-9.13
6.64
L.2@
a. 2 3
6.64
I .36
L.g4
a.gL
9.39
9.77
( roaHo)
Station
I.D.
r3aa
I 956
377L
6r52
6424
6844
6891
7 264
7386
77A6
8A62
Name
CaldweII
Coeur D'Alene
Ranger Station
Grangeville
Moscow-Uniy.
of Idaho
Nezperce
Parma Experiment
Station
Payette
PorthiII
Priest
River Exper.
Sta.
Riggins
Saint Maries
Winter
Summer
Year
-4.95
-9.13
a.L2
6.53
9.35
a.76
g.g8
9.93
g.g2
g.4L
9.32
a.2L
I .18
6.14
r.Lg
-9.43
-g.aL
4.52
9,43
g.a2
g.gg
-4,.23
-6.33
-9.35
-9.97
g.a4
4.79
4.56
g.16
-9.4r
4.29
-9.35
-q.r8
g.a2
g.a9
-9.16
( Nevaoa)
257 3
5869
6AA5
9L7t
ElKo FAA AP
Owyhee
Paradise
Valley
I
Winnemucca WSO Ap
-9.99
NW
a.13
9.23
-4.2a
a.6s
4.38
a.29
4.46
a.L5
( car,rroRNra)
L6T4
2L47
3157
376L
9953
9866
Cedarville
Crescent
City
IN
Fort Bidwetl
Happy Camp Ranger
Tulelake
Yreka
Station
c:8
a.24
-fr.33
a.g3
9.33
a.13
a.g6
I.28
s.34
L.g8
a.33
4.53
4.69
L.g6
-9.12
a.72
r.44
a.a9
-g.gL
MONTHLY SKEWNESS (L94A-L979)
Oct
Station
Jan
Apr
JuI
( oneeox)
A3A4
9328
A4L7
A47L
A694
LA55
l-862
1946
,2L68
2'997
3492
3827
45AG
4676
5162
5362
5429
6A32
6749
733f
8797
8997
9A68
2.66
a.86
I .93
L.A8
3.38
I .39
L.L2
1.55
L.22
L.A4
a.83
Ashland
Astoria
WSO AP
Baker KBKR
Bandon 2 NNE
Bend
Brookings
Corvallis-St.
Univ.
Crater
Lake NPS HQ
DayviIle
Forest
Grove
Camp
Government
Heppner
Klamath Falls
2 SSW
Lakeview
2 NNW
Malheur
Refuge HQ
McKenzj-e Bridge
R.S.
Medford WSO AP
Newport
KGW-TV
Portland
Roseburg KQEN
Vale
Wallowa
Wasco
o.57
a.89
-a.rg
I .5r
a.52
a.4r
g.4r
fr.23
2.65
L.gL
l.9r
I .38
a.2g
a.58
9.82
6.68
s.33
9.96
a,76
a.96
I .41
a.57
g.9r
a.43
6.3L
a.96
2.68
9.66
a.68
s.7a
A.IT
L.AA
a.33
a.a6
r.27
r.6a
r.79
a.86
L.27
I .48
a.18
a.37
9.44
a.56
a.44
a.56
2 .49
I .69
L.L7
2.46
9.55
a.92
2.35
r.74
a.78
L.79
g.BL
o.B3
2.67
L.25
r .99
2.32
L.42
4.18
3.66
r .55
L.4A
o.72
a.97
r.74
2.AA
r.74
L.62
I .43
2.18
L.46
L.4g
4.L4
2.28
r .15
L.57
( wasHrxoroN)
AA68
A564
L233
I395
L767
2L57
2914
4446
4549
5128
56f3
58OI
6LL4
6624
6896
7638
TLBg
7478
8931
9465
Aberdeen
Bellingham
2N
Cedar Lake
Chewelah
Coulee Dam t SW
Diablo
Dam
Forks I E
Lake Wenatchee
Laurier
Mazama 6 SE
Moses Lake 3 E
Neah Bay I E
Olympia
WSO AP
Port Angeles
Rainier-Ohanapecostr
(Tieton
Rimrock
Dam)
Rosalia
Seattle-Univ.
of Wash.
Walla Walla WSO CI
Yakima MO AP
fr.94
I.6L
9.52
a.99
L.49
9.72
L.g6
L.gL
L.3g
r.64
r .83
L.gI
g.5a
L.42
a.76
s.99
L.A3
s.75
9.93
I .36
c-9
g.7a
a.13
9.37
g.aL
g.aa
s.67
r .56
a.26
6.4r
9.55
9.78
o.96
A.TL
g.a5
a.49
9.37
a.58
g.5s
t.g4
9.34
a.64
L.9g
L.64
9.47
a.99
1.12
6.44
L.34
2.63
r.g7
a.B3
a.93
a.19
g.g4
9.36
L.64
r.3a
s.B3
a.95
a.a2
9.73
a.3L
s.58
q.64
o.74
r.g9
-9.93
9.73
r.a2
a.35
9.65
r.66
a.59
a.57
L.qq
a.6a
L.72
l.5r
r.49
r .53
APPENDIX D
CONFIDENCE INTERVAL OF MEAN PRECIPITA'TION
(all
data in inches)
D-l
of
Confidence Interval
(inches)
Mean Precipitation
( onecou)
Season
I.D.
A3A4
A328
w
S
Y
13.96
3.57
L7.94
16.8A
4.89
2L.68
L 7. 2 9
L3.47
5.11
3.35
L7.46 - 2L.62
W
S
Y
6L.73
LL.67
73.39
57.44
69.92
66.A2
L2.82
7 7. 7 6
55.96
ro.L2
6 7. 5 2
6 7. 5 4
L3.22
79.26
KBKR W
S
Y
6.69
4.64
11.37
6.AA
4.14
LA.4A
7.29
5.22
12.26
6.42
3.96
rg.r7
6.94
5.46
t2.57
53.A6
7.LL
6A.LA
49.63
6.27
56.84
56.43
7.95
9.42
48.45
5.98
55.69
57.67
8.24
64.67
8.53
3.42
r1.94
7.55
2.82
LA.74
9.51
4.gL
L2.T4
7.2r
2.6L
r9.33
9.85
4.23
13.55
69.A7
9.49
78.55
64.93
8.23
74.53
73.2L
L9.75
82.57
68.8A
7.79
73.16
76.34
1r.19
83.94
35.25
5.62
4A.86
32.38
4.92
38.A2
38.12
6:32
43.7A
3r.44
4.68
37.65
39.L4
6.56
44.67
58.63
9.63
68.26
54.35
8.57
64.32
62.9L
L9.69
72.29
52.88
8.2A
62.97
64.34
IL.g6
73.55
7.6L
4.35
r1.96
6 .88
3.76
16.92
8.34
4.94
13.ag
6.63
3.56
r9.57
8.59
5.14
13.35
38.7L
5.92
44.63
35.99
5.24
42.94
4L.43
6.6s
47.22
35.A5
5.Ag
4L.t6
42.37
6.44
48.rA
72.45
L5.52
87.96
67.r9
L4.27
82.74
'17
.7 r
L6.77 '
9 3 .I B
65.38
13.84
89.95
79.52
L7.29
94.97
9 .45
4.35
L3.8A
8.68
3.Bl
L2.94
L9.22
4.89
L4.66
8.42
3.62
L2.64
LA.4A
5.98
14.96
Astoria
WSO AP
Baker
g47I
Bandon
2 NNE
w
Bend
w
S
Y
S
Y
LO55
Brookings
W
S
Y
LB62
L946
Corvallis
State
Univ.
W
Crater
Lake
w
NPS HQ
2L68
Dayville
s
Y
S
Y
w
S
Y
2997
34A2
3A27
992
958
15.38
4.23
19.61
Ashland
A4I7
A694
Mean
Forest
Grove
Government
CamP
Heppner
w
S
Y
w
S
Y
w
S
Y
D-3
ra.52
I.D.
45A6
4679
5L62
5362
5424
6932
Season
Klamath
FalIs
2 SSW
w
Lakeview
2 NNW
w
S
Y
S
Y
Malheur
Refuge
HDQ
w
McKenzie
Bridge
R. S.
w
Medford
WSO AP
w
Newport
S
Y
S
Y
S
Y
w
S
Y
6749
Portland
KGW-TV
w
s
Y
7331
8797
Roseburg
KOEN
VaIe
w
S
Y
w
S
Y
8997
Wallowa
W
s
Y
9A68
Wasco
w
S
Y
958
Plean
992
LA.72
3.3A
14.A2
9.6A
2.78
L2.82
r1.84
3.82
15.22
9.22
2.6A
L2.49
L2.22
4.gg
L5.64
1r .41
4.33
l-5.74
r4.36
3 .81
14.51
L2.46
4.45
r6 .95
ra.aa
3.63
L4.69
L2.82
5.93
L7.37
5.87
3.42
9.28
5.23
3.A3
4.57
6.5r
3.8r
9.99
5.gL
2.89
8.33
6.73
3.95
L4.23
5 9. 3 2
L9.73
5 5 .1 6
9,68
66.16
63.48
11.78
73.94
53.73
9.32
64.82
64.9r
12.T4
75.28
14.89
14.33
2.72
L7.73
I8.65
4.24
22.2L
7s.a5
L6.49
3.48
l-9.97
18.31
l-8.a9
4.A5
2L.63
59.96
r4.35
7A.3I
55.66
9.99
65.99
64.26
1 1. 6 r
74.63
54.18
8.55
64.5A
65.74
L2.A5
76.12
3 5. 9 9
7.28
43.26
3 3. 3 5
6.4A
49.73
38.63
8.r6
45.49
32.43
6.ta
3 9. 8 6
39.55
4.46
46.66
28.49
4.69
33.rA
26.19
4.gg
3A.89
39.79
5.22
35.4A
25.4A
3.79
3A.AL
3I.58
5.43
36.19
6.46
2.95
9.4L
5.83
2.57
8.67
7.99
3.33
LA.L5
5.61
2.43
8.42
7.3L
3.47
LA.4A
11.98
6.35
I8.32
TL.05
5.8A
L7.24
T2.9L
6.9A
19.36
LA.72
5.5r
L6.92
l-3.24
7 .99
19.72
8.95
2.48
II.43
8.ra
9.8A
2.78
L2.32
7. 8 r
2.s7
2.9r
2.L8
L4.54
D-4
LA.23
r@.a9
2.49
l-2.63
(wesHrlqcror.r)
I.D.
aaqS
Season
w
Aberdeen
63.97
IT.77
76.99
72.23
L4.3L
85.29
62.54
tI .33
75.56
26.93
8.29
34.32
24.29
7.5r
32.2A
2 7. 7 7
9.A5
36.36
23.7A - 28.36
7.25
9.31
3r.57
3 7. A 7
L233
8A.63
22.A7
Y
r a z. 7a
75.87
85.39
2A.LI
24.A3
97.45 -Lg7 .95
74.24
87.A2
19.44
24.7g
95.65 -LAg.75
w
S
Y
14.15
6.11
29.26
L3.gL
5.43
18.98
r5.64
6.79
2L.54
12.62
5.19
18.54
t5 .68
7.A3
2L.98
w
s
6.9r
6.27
2.93
9.52
7.55
4.27
rr.48
6.A5
2.65
9.18
7.77
4.55
rr .82
w
BeI I ingham
2 N
Cedar
S
Y
Lake
W
s
I395
L767
Chewelah
Coulee Dam
I S W
2L57
Diablo
29L4
Forks
I
99t
68.rA
L3.64
B 1. 1 4
S
Y
a5 6 4
9st
Mean
Y
3.6A
Lg.5A
Dam
W
S
Y
68.85
IL.67
74 . 5 2
E
w
S
Y
9 7. 7 8
L B. 4 2
IL6.2g
58.12 - 67.58
L6.55
L2.79
69.43
79.6L
9L.52 -rg4.a4
L6.89 - 2a.94
L 6 9. 7 L - L 2 2 . 6 9
73.66
14.75
A6.72
56.5A
69.2A
Lg.I7 - 13.17
67.68
81.36
96.67 -1gl .89
16.24
2 A. 6 9
L A 7. 4 8 - L 2 4 . 9 2
4446
Lake
Wenatchee
W
S
Y
35.37
4.78
49.r5
3 2. 5 4
4.16
37.26 -
3 A. 2 s
5.40
43.A2
3r.57
3.94
36.27
39.17
5.62
44.9L
4549
Laurier
W
S
Y
TL.94
7.44
r9 .38
LL.g5
6 .57
L9.Lq -
r2.83
8.31_
2a.66
ra.75
1 3 .r 3
1 7. 6 6
2r.ra
Iql
S
15.24
4.23
19.47
13.88
3.4L
1 7. 8 5
L6.60
4.79
2L.99
r 3.41
3.18 16.99 -
L7.A7
5.A2
2L.64
5.78
2.45
8.23
5.19
2.A7
7.45
6 .37
2.83
9.gI
4.98
L.97
7.r9
6.58
2.93
9.27
5I2B
Mazama 6 SE
Y
5 6 13
58Ar
w
Moses Lake
3 E
Neah Bay
I
S
Y
E
w
S
Y
44.76
16.L7
LAA.93
D-5
78.84
9A.68
L4.79
r7.55
94.68 -rg7 .LB
6.27
8.61
76.8s
9 2 , 72
14.32 - l-8.a2
92.s3 -ro8.93
Season
I.D.
Mean
992
959
6LL4
Olympia
WSO AP
W
S
Y
4r .39
7.75
49.14
38.96
6.8r
45.75
4 4 . 73
8.69
52.53
36.93 6.48
44.59
45.47
9.A2
53.95
6624
Port
Angeles
w
S
Y
29.44
4.2r
24.65
LB.9A
3.79
23.62
2L.98
4.63
26.28
18.38 3.65
22.46
22.59
4.77
26.44
6896
Rainier
Ohanapecosh
W
S
Y
65.47
LL.A7
76.94
6L.A9
9.94
72.L5
7A.65
TL.2g
81.73
59.45
9.55
74.8A
72.29
L2.59
79.s8
7O38
Rimrock
(tieton
w
2L.67
3.5r
25.L2
I9.5I
3.A6
22.87
23.6r
3.96
2 7. 3 7
LA.79
3.45
22.09
24.43
4.12
28.15
12.79
5.23
LA.A2
LL.8g
4.59
L6.72
1 3. 7 8
5.87
L 9. 3 2
LI.46
4 .37
L 6. 2 7
L4.L2
6.99
L9.77
Dam) S
Y
7I8A
Rosalia
w
s
Y
SeattleUniv. of
Wash.
w
24.62
6.93
3 5. 5 6
26.86
6.12
33.62
3A.38
7.Ar
3 7. 5 A
26.26
5.8s
32.96
3A.98
S
Y
893r
WaIIa Walla
WSO CI
W
S
Y
r1.69
4.34
16.a3
lO.BI
3.79
L5.L2
L2.57
4.89
L6.94
Lg.5L
3.69
14.8r
L2,87
5.A8
L 7. 2 5
9465
Yakima
WSO AP
}I
S
Y
5.93
L.96
7.9s
5.28
1.63
7.L9
6.58
2.29
I .5r
5.95
I .5I
6.94
6 .8r
2.4L
B.86
7478
D-6
7.Ar
38.16
APPENDIX E
PRECIPITATION
SERIES
DATA SERIES FOR LONG-TERM STATIONS
DATA ARE ANI\{JAL TO'IAIS
ARE SMOOTHEDWITH g-TERM WEIGH'TED MEAN
E-l
WesternOregon
E- 3
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o
s
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