The Colorado Drought
2001-2003:
A Growing Concern
Roger Pielke, Sr.
Colorado Climate Center
Prepared by Tara Green and Odie Bliss
http://climate.atmos.colostate.edu
2
2002 Drought History in Colorado
– A Brief Summary
3
EXAMPLES OF DROUGHTS
 Snow does not fall in the mountains until
late January
 It is dry in April-July, but soaking rains
occur in eastern Colorado in August
 The weather of 2001-2002 repeats for
the next five years
 Colorado’s mountains have 90% of
average snow for the next 20 years.
4
April 1 Snowpack
APRIL 1 SNOWPACK COLORADO STATEWIDE
160
148 146
140
130
127
126
120
114
Percent of Average
109
109
104
100
126
120
119
106
112 114
105
104 104
99
97
95
91 93
87
85 87
80
90
89
84
87
74
65
59
60
53
46
40
20
0
68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02
Year
5
Drought Status on April 1,
2002
 Entire State Dry
 Statewide Snowpack

53% of Average
 Bad, but not as bad as 1977
 Optimism for a wet spring – esp. in N.
Colorado
6
But then came April
 Very warm – especially in Mountains
 Very Dry
 Rapid Snowmelt
 Little Runoff
7
May also failed us
 Only one significant storm
 High evaporation rates
 Severe drought arrived !!
8
June 2002
 Some heavy rains on plains but little plant growth
 Evaporation rates very high
 Many grass fires
 Even when some heavy rains did come
to eastern Colorado in early June, the ground was so
hard, the vegetation on grazed lands was so short and
the rains fell for such a short period of time, that little of
the moisture soaked in – and vegetation remained
parched. Grass fires popped up all over eastern
Colorado, keeping local fire fighters on their toes.
 Extreme Drought in Mountains
 Forest Fires exploded
9
By late June 2002
 Raging wildfires
 Extreme low streamflows
 Rapidly depleted
reservoirs
 Severe agricultural
impacts
 Wheat
 Cattle
 Irrigated crops in
jeopardy
 Intense heat
 Urban water restrictions
Hayman Fire
Largest in Recent History
10
Widespread Drought
 By late July
2002,
Colorado near
epicenter of
extensive
regional
drought
 Parts of nearly
every state
experiencing
drought
11
August 2002 Pattern Changes
 More extreme heat




early
Another wildfire flare
up
Severe storms late in
August
Real relief in portions
of the Eastern Plains
But most of Colorado
still in extreme
drought
Steamboat Springs Fire
Photo from Steamboat Springs Fire Department
12
The 1977 Drought
13
Total Precipitation Analysis
September 2001 – August 2002 Ranking by Station
Climatic Stations
Year of Record
Rank
Amount of Precipitation
Grand Lake 1 NW
1940-2002
1
12.55
Taylor Park
1941-2002
1
10.42
Grand Junction WSO A
1892-2002
8
5.54
Meeker
1891-2002
7
10.37
Montrose No. 2
1896-2002
3
5.83
Mesa Verde NP
1923-2002
1
7.43
Del Norte 2 E
1940-2002
1
3.19
Center 4 SSW
1891-2002
1
2.44
Colorado Springs WSO
1892-2002
1
6.5
Pueblo WSO
1891-2002
1
3.8
Rocky Ford 2 SE
1892-2002
1
3.62
Cheyenne Wells
1897-2002
4
9.16
Akron 4 E
1905-2002
1
9.4
Leroy 7 WSW
1891-2002
3
10.58
Kassler
1899-2002
8
12.56
14
September 2002
Wet Weather at Last
15
Colorado Water Year 2002
(Oct. 2001-Sept. 2002)
Precipitation Percent of Average for the 1961-1990 Averages
16
Where are we now?
17
Through 1999
18
19
20
21
22
Colorado River Basin Snow
Availability
RIVER BASIN
March 2, 2003
Number of
Sites
Snow Water
Equivalent
% of Average
GUNNISON RIVER BASIN
11 of 12
85
UPPER COLORADO RIVER BASIN
25 of 27
89
SOUTH PLATTE RIVER BASIN
15 of 16
81
LARAMIE AND NORTH PLATTE RIVER BASINS
13 of 13
86
YAMPA AND WHITE RIVER BASINS
13 of 14
88
ARKANSAS RIVER BASIN
6 of 6
90
UPPER RIO GRANDE BASIN
10 of 10
77
SAN MIGUEL, DOLORES, ANIMAS,
AND SAN JUAN RIVER BASINS
15 of 15
75
23
Source: http://www.wrcc.dri.edu/snotelanom/snotelbasin
24
25
26
Cheesman
2003 Water Year
(through October '02-February '03)
35
30 Year Averages-1971-2000
Max Year - 1970
25
Min Year - 2002
20
Period of Record Average - 1904 2002
2003 Water Year
15
10
5
SE
P
G
JU
L
JU
N
AY
AU
Months
M
AP
R
AR
M
FE
B
N
JA
C
DE
V
NO
CT
0
O
Accumulated Precipitaton
(Inches)
30
27
Cheyenne Wells
2003 Water Year
(through October '02-February '03)
Accumulated Precipitation
(Inches)
35
30 Year Averages-1971-2000
30
Max Year - 1909
25
Min Year - 1956
20
Period of Record Average - 1971 - 2002
15
2003 Water Year
10
5
0
OCT
NOV
DEC
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
Months
28
Boulder
2003 Water Year
(through October '02-February'03)
35
2003 Water Year
30
Accumulated
Precipitation (inches)
30 Year Averages-1971-2000
Max Year - 1995
25
Min Year - 1966
20
Period of Record Average - 1894-2002
2002 Water Year
15
10
5
0
C
O
T
N
V
O
D
EC
N
JA
B
FE
AR
M
R
AP
AY
M
JU
N
JU
L
G
AU
P
SE
Months
29
3 Month SPI
30
12 Month SPI
31
48 Month SPI
32
COLORADO NEEDS
 What would be the impact today of historical




droughts?
What would be the impact today of paleodroughts?
What if the 2001-2002 dry, warm weather
reoccurred for 2002-2003?
How can we make Colorado more resilient to
droughts?
What are the definitions of the multidimensional character of droughts.
33
Vulnerability Assessment
 A vulnerability assessment of risk to
climate and other environmental stress
is, therefore, more appropriate as guides
to Policy Makers, than trying to predict
only a subset of possible future climate
conditions.
34
Image by Jan Null, CCM
http://ggweather.com/winter0203.htm
35
Image by Jan Null, CCM
http://ggweather.com/winter0203.htm
36
Image by Jan Null, CCM
http://ggweather.com/winter0203.htm
37
In Conclusion
 Sept 1, 2001 to August
30,2002 was the driest
for that period at most
climate observing sites in
Colorado.
 Over a several year time
period, however, the
current drought is a
garden variety drought. It
is not exceptional.
 Weather modification will
not break a drought. At
best, it slightly
increases snowpack.
 The current drought is
not a consequence of a
warmer atmosphere. In
fact, the Earth's
atmosphere is no warmer
today than it was in 1979.
 Models which have been
used to predict climate a
year or more in the
future have demonstrated
no skill in forecast ability.
 We should adopt
vulnerability assessments
as the preferred
paradigm,
rather than primarily
focusing financial
resources on prediction.
38
Colorado Climate Center
Colorado State University
 Data and Power Point Presentations available for
downloading
http://climate.atmos.colostate.edu
click on “Drought”
then click on “Presentations”
39