Dry thunderstorm outbreak after prolonged dry
conditions is Critical in all areas
Winds > 10 mph, RH < 30%,
KBDI > 600
Winds > 25 mph, RH < 15%, 10 hr fuels
< 7%
Beware when in green-up conditions.
20 ft winds > 20 mph,
RH < 25%, 10 hr
fuels < 9%
RH may be raised during Drought or extreme conditions
Winds > 25 mph, RH < 15 %
Winds > 20 mph, RH < 20%
Riverside
Winds > 25 mph, RH
< 15%
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
NFDRS High to Extreme
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
Florida
RH < 35% for 4 hrs, RH <
35% with winds > 15 mph
DI > 75 (dispersion index)
Winds > 20 mph, RH < 25% for 4 hrs
Dry Cold front (winds > 20
mph and gusty with RH < 15%)
Strong winds and low RH by themselves
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
NFDRS High to Extreme
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
NFDRS High to Extreme
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
NFDRS High to Extreme
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
NFDRS High to Extreme
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
Winds > 20 mph, RH < 25%
Vegetative Stage I or II (cured/transition…spring/fall)
Winds >25 mph
RH < 30%
Rain
< 0.25 “ past 5 or more days
Vegetative Stage III (green-summer)
Winds >25 mph
RH < 30%
KBDI >300
Mean 1 and 10 hr fuels < 10 %, with
RH 33-39% Winds >30 mph
RH 27-32% Winds > 20
RH 20-26% Winds > 10 mph
RH < 20%, then wind is not a factor
In Maryland, 10 hr fuels < 10%, winds > 25 mph, RH
< 30%
Vegetative State I and II (cured and
pre-greenup{spring and fall})
Winds sustained or frequently gusting >25 mph
RH < 30%
Rain
past 5 days < 0.25 “
Vegetative State III (Green: Summer)
Winds sustained or frequently gusting >25 mph
RH < 30%
Rain
past 8 days <0.25”
KBDI of >300
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20 mph,
RH <20%, Temp > 80 F, 10 hr fuels < 9%
NFDRS High to Extreme
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
Winds > 20 mph or changing
directions, RH < 20 %
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
NFDRS High to Extreme
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
Winds > 20 mph gusts >
30 mph, RH < 15%,
Dry storms over at least 15 % of the area
Wind >25 mph sustained for
2 hrs, RH < 30%, 10 hr time lag moisture < 10 %
Most of the SW Area has RH <
15%, Winds > 20 mph.
Beware when in greenup conditions.
Vegetative Stage I or II (cured/transition…spring/fall)
Winds >25 mph
RH > 30%
Rain
< 0.25 “ past 5 or more days
Vegetative Stage III (green-summer)
Winds >25 mph
RH < 30%
Rain
<0.25 in past 8 or more days
KBDI >300
Winds > 20 mph and/or
gusting >30 mph, RH < 25%
Wilmington, NC (ILM)
Winds > 20 mph for 6 hrs,
RH < 25%
Sig. wind shift during fire
suppression efforts
In NC…RH < 25%, winds >20 mph or gusting to >30 mph
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
NFDRS High to Extreme
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
10 hr < 8% for 2 days,
RH < 25%, Winds
> 15 mph for 2 hrs
10 hr fuels 8%, RH < 25%, 20 ft wind
>15 mph
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
NFDRS High to Extreme
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
Green Season- Winds > 20
mph, RH < 20%, Temp > 95 F, KBDI > 450
Dormant - Winds > 20 mph,
RH < 20%, Temp > 80, KBDI > 250
Portland
Strong easterly dry winds,
Dry cold front, Very dry and unstable airmass
Winds > 20 mph, RH < 20%, or
Very low RH < 10% and or Max RH is < 35%
Winds > 20 mph, RH < 15%,
Moderate winds and dry conditions at night (> 10 mph and < 40%
RH)
10 hr fuel <8%, RH
<25%, 20 foot sustained winds >15 mph
10 hr fuels < 8% for 2
days, RH <25%, 20 ft wind >25 mph sustained
10 hr time lag moisture <
10%, wind >25 mph sustained for 2 hrs
RH < 25%
RH < 25%, winds >20mph
Winds 25 mph, Significant
shift in wind direction, RH < 25%
Big increase in Temperature, after extended dry period
Charleston, SC (CHS)
Winds > 20 mph 6 hrs, Significant
wind shift, RH < 25%
Average Criteria for CR- Combination of 3 or more of
the following:
Sustained 20 ft winds >20
mph, RH <20%, Temp > 80 F, 10 hr fuels < 9%
1-2 weeks of dry weather
MDT to HIGH Haines (5 or 6)
850 Td depression >10 C
LAL 6
Winds > 25 mph, RH < 25%
Winds > 25 mph, RH <25%
AMA Amarillo
Winds sustained ~ 20 mph,
RH < 20-25%
Winds > 20 mph, RH < 15%
RH < 15%, 20ft Winds > 25 mph, 10
hr fuels < 7 %
20 ft winds > 20 mph,
RH < 15%
RH < 30% inland ( 40% coast),
Winds > 25 mph
Winds > 25 mph, RH < 30%
Drought conditions
Should be abundance of cured dry fine fuels
RH < 20%, Winds > 20 mph
Extensive storms with
microbursts > 50 mph,
Winds > 20 mph gusting 35
mph, RH < 15%
Vegetative State I and II (cured and pre-greenup{spring
and fall})
Winds sustained or frequently gusting >25 mph
RH <30 %
Rain
past 5 days < 0.25 “
Vegetative State III (Green: Summer)
Winds sustained or frequently gusting >25 mph
RH < 30 %
Rain
past 8 days <0.25”
KBDI of >300
SFC winds > 25 mph,
RH < 30%, 10 Hr
fuels < 8 %
In WV and VA…
10 hr 7%
RH < 30 %
Winds sustained >25 mph
Sustained winds >35 mph
with any RH value.
10 hr fuels < 7 %, winds > 35 mph with
no RH restriction, or
25 mph with < 30 % RH
RAWS winds > 10 mph
with RH < 35% or
RH < 30 %, except RH < 25% on the Gifford Pincho NF south of the
Cowlitz River
Winds > 15 mph and RH < 15%
10 hr fuels 7%, RH <
30%, winds sustained >25 mph
OR…
Sustained winds >35 mph
with any RH value.
Western WY
RH < 15%, winds > 25 mph
Haines 5 or 6
12-2001