GFMC: Forest Fires in the United States, 3 January 2001
Forest Fires in the United States
3 January 2001
The Wildland Fire Assessment System (WFAS) is a contribution of “The Fire Behavior Research Work Unit”, Missoula (Montana USA). The broad area component of the Wildland Fire Assessment System (WFAS) generates maps of selected fire weather and fire danger components.
Fire Danger (Potential) is a normalized adjective rating class across different fuel models and station locations. It is based on information provided by local station managers about the primary fuel model, fire danger index selected to reflect staffing level, and climatological class breakpoints. Low danger (class 1) is green and extreme potential (class 5) is red.
Fire danger maps for the United States for 2 January 2001 (observation time) and 3 January 2001 (forecast)
Dead fuel moisture responds solely to ambient environmental conditions and is critical in determining fire potential. Dead fuel moistures are classed by timelag. A fuel’s timelag is proportional to its diameter and is loosely defined as the time it takes a fuel particle to reach 2/3’s of its way to equilibrium with its local environment. Dead fuels in NFDRS have four timelag classes:
1-hr: Fine flashy fuels, less than 1/4″ (< 0.63 cm) diameter. Responds quickly to weather changes. Computed from observation time temperature, humidity and cloudiness.
10-hr: 1/4 to 1″ (0.63 to 2.54 cm) diameters. Computed from observation time temperature, humidty, and cloudiness, or may be a standard set of “10-Hr Fuel Sticks” that are weighed as part of the fire weather observation.
100-hr: 1 to 3″ (2.54 to 7.62 cm) diameter. Computed from 24 hour average boundary condition composed of day length, hours of rain, and daily temperature/humidity ranges.
1000-hr: 3 to 6″ (7.62 to 15.24 cm) diameter. Computed from a 7-day average boundary condition composed of day length, hours of rain, and daily temperature/humidity ranges.
10-HR Fuel Moisture
100-HR Fuel Moisture
1000-HR Fuel Moisture
Fuel moisture maps for conterminous US, 2 January 2001
The Keetch-Byram Drought Index (KBDI) is a soil/duff drought index that ranges from 0 (no drought) to 800 (extreme drought) and is based on a soil capacity of 8 inches of water. Factors in the index are maximum daily temperature, daily precipitation, antecedent precipitation, and annual precipitation. KBDI = 0 – 200: Soil moisture and large class fuel moistures are high and do not contribute much to fire intensity. Typical of spring dormant season following winter precipitation. KBDI = 200 – 400: Typical of late spring, early growing season. Lower litter and duff layers are drying and beginning to contribute to fire intensity. KBDI = 400 – 600: Typical of late summer, early fall. Lower litter and duff layers actively contribute to fire intensity and will burn actively. KBDI = 600 – 800: Often associated with more severe drought with increased wildfire occurrence. Intense, deep burning fires with significant downwind spotting can be expected. Live fuels can also be expected to burn actively at these levels.
For further information on the Keetch-Byram Drought Index (KBDI) by Florida’s Division of Forestry / Forest Protection Bureau please refer to Keetch-Byram Drought Index Revisited: Prescribed Fire Applications.
Keetch-Byram Drought Index Maps for conterminous US, 2 January 2001
Operational Significant Event Imagery (OSEI)
The following significant events were identified by Satellite Analysis Branch meteorologists and reviewed by the OSEI support team:
NESDIS/OSEI NOAA-14 POES AVHRR LAC satellite image, 29 Dezember 2000.
Heat signatures (red) are visibls from a fire burning east of Kolik, Alaska.
According to the U.S. Fish and Wildlife Service in Alaska, the fire has consumed approximately
20,000 acres on the Yukon Delta National Wildlife Refuge. A backfiring snowmachine was blamed
for causing the fire on 27 December 2000. High winds at over 25 mph caused the fire to spread over 10 miles.
Wildfire burning on snowless Alaska tundra (published by PlanetArk, January 1, 2001)
ANCHORAGE, Alaska – Unusual snowless conditions have allowed a 9,000-acre (3,600 hectare) wildfire to burn on the tundra of western Alaska, federal officials said on Friday. Firefighters were monitoring the blaze, which is located on the southern edge of Norton Sound and near the mouth of the Yukon River, about 430 miles (695 km) northwest of Anchorage. The fire is burning in the Yukon Delta National Wildlife Refuge. The closest settlement is Kotlik, a Yupik Eskimo village of about 450 people, located 20 miles (32 km) to the west of the fire. No threats to people or property have been identified, but the fire is being watched because of concerns about critical wildlife habitat in the refuge, said Andy Williams, spokesman for the Alaska Fire Information Center. Alaska’s normal wildfire season is in late spring and early summer, when full greenery has yet to bloom. A winter fire is an oddity, Williams said.