Fire and Weather Analyses
Southwestern Crown of the Continent
Swan Lake Ranger District, Flathead National Forest
Lincoln Ranger District, Helena National Forest
Seeley Lake Ranger District, Lolo National Forest
January, 2013
LaWen Hollingsworth, Fire Behavior Specialist, Rocky Mountain Research Station, Fire Modeling Institute, Missoula, MT
Hollingsworth 2013
Fire and Weather Analyses
Introduction
Weather and fire occurrence records were acquired and analyzed for the Flathead (FNF), Helena (HNF),
and Lolo (LNF) National Forests in western Montana in support of a Collaborative Forest Landscape
Restoration (CFLR) Program project. In order to provide a framework for weather parameters to be
used in point and spatial fire behavior analyses, it is often helpful to complete an analysis evaluating fire
growth and fire behavior in relation to observed weather. Not only it is easy to identify record-setting
years for fire occurrence, but it is also possible to examine the weather that occurred during large fire
years including weather that promoted large fire growth as well as weather that did not.
This analysis couples weather station data and fire occurrence data from multiple sources. Fire
occurrence data and daily 1300 weather data were downloaded from the Fire and Weather Data on the
FAMWEB website (refer to https://fam.nwcg.gov/fam-web/) for the FNF, HNF, and LNF as RAW files to
be imported into FireFamilyPlus v. 4.1.0. Hourly weather observations were downloaded from the
Western Regional Climate Center (WRCC) for each individual weather station and imported into
FireFamilyPlus. Observational fire behavior and fire weather data is provided through direct accounts
and the ICS-209 system (refer to http://fam.nwcg.gov/fam-web/hist_209).
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Swan Lake Ranger District, Flathead National Forest
The FNF had active fire years in 2003 and 2007 and the Swan Lake RD had an active year in 2003 (Figures
1 and 2, respectively). Most fires are caused by lightning and occur from June through August with a
long shoulder season on either side.
Figure 1. Fire occurrence on the FNF from 1970 to 2011
Figure 2. Fire occurrence on the Swan Lake RD from 1970 to 2011
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Fire and Weather Analyses
Crazy Horse
The Crazy Horse Fire started 8/10/2003 and burned south of Condon, Montana (Table 1). This fire
burned mostly in subalpine fir, lodgepole pine, and Douglas-fir with areas of heavy dead, down fuels.
Table 1. Acres and critical fire behavior and weather as reported in the ICS-209 reports for the Crazy Horse Fire
Date and Time
Cumulative Acres
Fire Behavior and Weather Comments
8/10/03 2245
Total – 750 ac
Extreme fire behavior
8/11/03 0000
Total – 1,500 ac
8/12/03 1649
Total – 4,000 ac
8/13/03 2000
Total – 7,000 ac
8/14/03 1630
Total – 7,700 ac
8/15/03 1700
Total – 7,900 ac
8/16/03 1800
Total – 9,475 ac
8/17/03 1800
Total – 9,807 ac
8/18/03 1700
Total – 9,855 ac
8/19/03 1800
Total – 9,926 ac
FINAL
Total – 11,300 ac
Extreme fire behavior, 2.5 mile run in 2 hrs
74 degrees, 18% RH, SW wind 3-5 mph
Moderate fire behavior, spread with wind >5 mph
75 degrees, 37% RH, upslope wind 4-9 mph
Lost all constructed fireline, intense surface fire
Medium range spotting, extreme fire behavior
85 degrees, 24% RH, W wind 3-7 mph
Active and passive crowning, intense surface fire
Low live and dead fuel moistures
90 degrees, 16% RH, NW wind 3-6 mph
Short-range spotting, fire shaded by smoke
95 degrees, 16% RH, SE wind 5-8 mph
Short-range spotting, moderate fire behavior
83 degrees, 22% RH, W/NW wind 10-15 mph
Moderate fire behavior, light precipitation
Short-range spotting
85-92 degrees, 12-20% RH, SW wind 6-12 mph
Moderate fire behavior, intermittent torching
Short-range spotting
87 degrees, 23% RH, N wind 3-5 mph
Winds caused increased torching and short-range spotting
90 degrees, 15% RH, SW wind 5-10 mph
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Fire and Weather Analyses
Lincoln Ranger District, Helena National Forest
The HNF had active fire years in 1984, 1988, 1990, 2000, 2003, and 2007 and the Lincoln RD had active
years in 1988 and 2003 (Figures 3 and 4, respectively); 2003 has the best available data and so will serve
as the analysis year. Most fires are caused by lightning and occur from June through August with a long
shoulder season on either side.
Figure 3. Fire occurrence on the HNF from 1970 to 2011
Figure 4. Fire occurrence on the Lincoln RD from 1970 to 2011
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Fire and Weather Analyses
Snow-Talon
The Snowbank and Talon Fires started 8/13/2003 and burned west of Lincoln, Montana (Table 2). The
fires merged early and were managed as the Lincoln Complex together with the Moose-Wasson Fire.
This fire burned mostly in subalpine fir, lodgepole pine, and Douglas-fir with areas of heavy dead, down
fuels.
Table 2. Acres and critical fire behavior and weather as reported in the ICS-209 reports for the Lincoln Complex
Date and Time
Cumulative Acres
Fire Behavior and Weather Comments
8/14/03 2000
Total – 2,000 ac
Erratic fire behavior, torching with major runs
93-101 degrees, 22% RH, SE 5-15 mph
8/15/03 2315
Total – 7,500 ac
Torching, major runs
88 degrees, 22% RH, SE wind 0-5 mph
8/16/03 1800
Total – 7,500 ac
Moderate fire behavior, creeping and torching
77 degrees, 48% RH, SW wind 2-5 mph
8/17/03 2000
Total – 5,223 ac
Moderate fire behavior, short-range spotting
(more accurate mapping) 80 degrees, 25% RH, W wind 3-6 mph
8/18/03 1800
Total – 9,525 ac
Significant runs, spotting
79 degrees, 24% RH, SW wind 5-8 mph
8/19/03 1800
Total – 11,080 ac
Sustained crown runs, short-range spotting
86 degrees, 26% RH, W wind 4-8 mph
8/20/03 1800
Total – 30,369 ac
Sustained crown runs, spotting
Large growth with thunderstorm passage last night
79 degrees, 20% RH, W/SW wind 10-15 mph
8/21/03 1800
Total – 32,145 ac
Short upslope crown runs, torching
85 degrees, 20% RH, W wind 10-12 mph
8/22/03 1800
Total – 33,252 ac
Precipitation received, smoke inversion
80 degrees, 25% RH, S/SW wind 11 mph
8/23/03 1800
Total – 33,252 ac
Wetting rain last night moderate fire behavior
More active due to increasing gusty winds
74 degrees, 26% RH, W wind 8 mph, gust 18 mph
8/24/03 1800
Total – 33,252 ac
Short-range spotting, group torching, moderate ROS
85 degrees, 26% RH, W wind 5-10 mph, gust 16 mph
FINAL
Total –ac
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Fire and Weather Analyses
Seeley Lake Ranger District, Lolo National Forest
The LNF had active fire years in 1988, 2000, 2003, and 2007 and the Seeley Lake RD had active years in
1988, 2000, and 2007 (Figures 5 and 6, respectively). Most fires are caused by lightning and occur from
June through August with a long shoulder season on either side.
Figure 5. Fire occurrence on the LNF from 1970 to 2011
Figure 6. Fire occurrence on the Seeley Lake RD from 1970 to 2011
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Fire and Weather Analyses
Canyon Creek
Although Yellowstone NP received much of the publicity for wildfires in 1988, an interesting sequence of
events occurred as well on the SWCC. The Canyon Creek Fire started in early June on the Lolo NF and
met prescription criteria to be managed as a prescribed natural fire. It should be noted that the area
had been in a drought for the last three years, recording 56% of normal precipitation the previous
winter. Still only 4-5 acres in early July, the first big run of 10,000 acres occurred in the third week of
July. The expected “August singularity” did not materialize to bring rain to western Montana in midAugust. On August 9, 30-mph winds pushed the Canyon Creek Fire into the Dearborn River drainage on
the east side of the continental divide (approximately 33,000 acres at this time). By the end of August,
the fire had grown to 51,000 acres. On Sept 6, a low elevation jet reportedly surfaced and the fire grew
118,000 acres in the next 16 hours. Sustained winds of over 50 mph were reported during the passage
of the dry cold front and in one observed run, the fire covered 21 miles in 5 hours. In the end the
Canyon Creek Fire stopped about 5 or 6 miles from the community of Augusta and burned through
portions of the Lolo NF (Seeley Lake RD), Helena NF (Lincoln RD), and Lewis and Clark NF (Rocky
Mountain Front RD). Locals reminisce of another wildfire that burned in 1898, reportedly burned in a
similar fashion stopping short of the communities of Augusta and Choteau.
Conger Creek
Jocko Lakes
This fire started on Confederated Salish and Kootenai Tribal lands approximately 8 miles west of Seeley
Lake, Montana on 8/3/2007 and burned a mix of the LNF, tribal lands, and state DNRC lands. Jocko
Lakes burned through spruce and lodgepole with coarse woody debris.
Date and Time
8/3/07 1919
Cumulative Acres
Total – 800 ac
8/4/07 2000
Total – 8,000 ac
8/5/07 1807
Total – 18,000 ac
8/6/07 1757
8/7/07 1725
Total – 15,000 ac
(more accurate mapping)
Total – 15,000 ac
8/8/07 1703
Total – 16,800 ac
8/9/07 1900
Total – 18,600 ac
8/10/07 1900
Total – 19,330 ac
8/11/07 1900
Total – 19,540 ac
8/12/07 1900
Total – 20,800 ac
Fire Behavior and Weather Comments
High ROS, long-range spotting (2 miles), crowning
85 degrees, 12 % RH, SW wind 40 mph
Extreme fire behavior, long-range spotting (2 miles), crowning
Fire growth to the south against prevailing winds
85 degrees, 20% RH, W/SW wind 10 mph
Moderate fire behavior, fire shaded by smoke
70-80 degrees, 12-22% RH, E/NE wind 3-7 mph
Inversion, heavy smoke limited fire spread
75-85 degrees, 12-22% RH, SW/W wind 5-15 mph
Group torching, short-range spotting, increasing winds
80-90 degrees, 12-22% RH, W wind 5-15 mph
Group torching, short-range spotting
75-85 degrees, 20-30% RH, SW wind 5-15 mph
Short-range spotting, moderate fire behavior
86 degrees, 19% RH, SW wind 10 mph
Short-range spotting, single/group torching
75 degrees, 24% RH, NW wind 10 mph, gust to 20 mph
Single/group torching
83 degrees, 11% RH, S wind 5-15 mph
Single/group torching, short-range spotting, testing fireline
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8/13/07 1900
Total – 21,270 ac
8/14/07 1900
Total – 22,100 ac
8/15/07 1900
Total – 24,190 ac
8/16/07 1900
Total – 25,170 ac
8/17/07 1900
Total – 27,140 ac
8/19/07 2030
Total – 31,520 ac
FINAL
Total – 36,388 ac
88 degrees, 10% RH, W wind 10-24 mph
Single/group torching, short-range spotting, testing fireline
87 degrees, 10% RH, SW wind 9-15 mph
ROS 75 ch/hr
Single/group torching, short-range spotting, testing fireline
87 degrees, 10% RH, SW wind 6-15 mph
Inversion until 1600, active spread after that
89 degrees, 8% RH, variable wind 10-16 mph
Single/group torching, short-range spotting 200-400 yards
Smoky skies, column
86 degrees, 17% RH, variable 4-10 mph
Single/group torching, short-range spotting 200-400 yards
Active nighttime fire behavior
90 degrees, 17% RH, W wind 10-15 mph
1400 – the fire made a run out of Boles Creek with crown fire,
multiple fire whirls and spotting pushed by 20 to 25 mph winds
Jumped containment lines in SE corner
77 degrees, 19% RH, W wind 8 mph, gust 18 mph
Weather
Weather data including the daily observation and weather station catalog information was downloaded
from FAMWEB as fw9 files to be imported into FireFamilyPlus. Usually representing 1300 weather,
these observations are the official record and include manual corrections to fix errors within the data.
Additional weather information was downloaded for multiple weather stations from the Western
Regional Climate Center (http://www.raws.dri.edu/) for analyses in FireFamilyPlus. The WRCC data
includes hourly observations from weather stations that have not been corrected. FireFamilyPlus was
used to analyze the data to identify anomalous data, determine critical weather thresholds affecting fire
growth and fire behavior, and prepare wind and weather files for geospatial fire analyses.
Another source of information is the Wildland Fire Assessment System (refer to http://www.wfas.net/).
The Keetch-Byram Drought Index (KBDI) is a value quantifying cumulative moisture deficiency in deep
duff and upper soil layers. KBDI values for mid-August of 2003 display values ranging mostly between
301 to 500 although there are some pockets identified with KBDI values <500 or >700. At these levels
the litter and duff layers are expected to burn actively and spotting is predicted with KBDI >600.
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Fire and Weather Analyses
Figure 9. KBDI values in August, 2003
The Palmer Z Index is a metric provided by the NOAA National Climatic Data Center (refer to
http://www.ncdc.noaa.gov/oa/climate/research/prelim/drought/palmer.html for information and
http://www.ncdc.noaa.gov/temp-and-precip/drought/historical-palmers.php for historical data). The
Palmer Z provides a means to evaluate short-term drought based on how the monthly cumulative
a)
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Fire and Weather Analyses
b)
c)
Figure 10. Palmer Z Indices for a) July, 2003, b) August, 2003, and c) September, 2003
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Fire and Weather Analyses
a)
b)
Figure 11. Maps depicting a) relative greenness and b) departure from average greenness
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Fire and Weather Analyses
precipitation deviates from normal. While central Oregon was plagued by a severe to extreme drought
in July to August of 2003, moisture conditions improved through the summer and were considered
neutral by September (Figure 10). However, the short-term drought signals that live moisture values
were probably below normal which allowed for substantial fire activity in July and August.
Relative greenness maps compare current to historical greenness conditions. The relative greenness
maps for western Montana in 2003 generally show values >80 percent with some pockets ranging from
70 to 80% (Figure 11a). Departure from average greenness in this area is greater than 100% (Figure
11b). This value compares how green each pixel is compared to its average greenness for that week of
the year. Observed 100-hr fuel moisture values range between 6 and 10% (Figure 12).
Figure 12. Observed 100-hr fuel moisture values
Geospatial fire behavior analyses require wind and weather information. In order to prepare files as
required by systems such as FARSITE or FlamMap, hourly wind data and daily weather data can be
exported in FireFamilyPlus using the FARSITE Exports function in Weather > Hourly Data Analysis. These
files were prepared and named RoundMtnRAWS2003.wnd (wind file) and ColgateRAWS2003.wtr
(weather file).
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Glossary
Burning period – corresponds to the length of time each day when a fire is actively spreading.
Coarse woody debris – dead wood greater than 3 inches in diameter or 1000-hr timelag fuels.
Live fuel moisture – herbaceous and live woody fuels; 100% refers to mature foliage with new growth
complete.
Timelag fuels – the length of time needed under consistent conditions for a fuel particle to lose about 63
percent of the difference between its initial moisture content and its equilibrium moisture content. For
dead roundwood fuel:
1-hr = <0.25 inch diameter
10-hr = 0.26 – 0.99 inch diameter
100-hr = 1-3 inches diameter
1000-hr = 3-8 inches diameter
Wind adjustment factor – adjusts the 20-ft windspeed to midflame windspeed depending on the
sheltering of fuels from the wind.
0.1 - fully sheltered, dense stands
0.2 - fully sheltered, open stands
0.3 - partially sheltered
>0.4 - unsheltered
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