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 14 December 2000 (observation time) and 15 December 2000 (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, 14 December 2000
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, 14 December 2000
National Weather Service Long-range, 30-day weather forecasts are predicting above-normal temperatures for the southern tier of states from southern California to Florida and throughout the Midwest (see 30 and 90-day forecast maps).
30 and 90-day temperature and precipitation forecast maps (October and October to December 2000)
(Source: National Weather Service)
USFS National Incident Information Center – Fire and Aviation Management (8 November 2000) [conversion table]
The National Incident Information Center is currently closed and will re-open in the Spring of 2001 or when fire activity becomes significant. 2000 Fire Season Summary The fire season of 2000 was historic in acres burned, number of large fires burning, international fire fighter participation, military involvement and national interest. Public reaction to the heroic efforts of the fire fighters and renewed enlightenment to the plight of our nation’s forests brought people together as no national event had in recent years.
The winter of 1999-2000 was dominated by the La Nina weather pattern. It caused drought in the southern half of the country and produced a wet winter in the northwestern United States. The combination of hot weather, dry fuels and little rainfall produced one of the most severe wildland fire seasons in U.S. history. Mid-February – March Fire activity began with large grass fires in New Mexico. Fire activity moved eastward and northward into Virginia. By the end of February, fires were reported in Texas, Louisiana and Missouri. March saw several fires burning in Oklahoma and the year’s first Type 1 team was assigned to a fire on the Kisatchie National Forest in Louisiana. Other large fires were reported in Georgia, Florida, Alabama, Missouri, Ohio, Minnesota and Indiana. April Type 1 Incident Management Teams managed the wind-driven Cabbage fire on the Mendocino National Forest, California and the Coon Creek fire on the Tonto National Forest, Arizona. There were large fires burning in Minnesota, Wisconsin, Mississippi, New Mexico, Missouri, Kentucky, Florida, Colorado, North Carolina and North Dakota. May The season began in earnest with an escaped prescribed fire on the Bandelier National Monument near Los Alamos, New Mexico. Attempting to reduce thick brush, fire personnel ignited a fire on May 4 that was driven by erratic winds across control lines. By the time the fire was controlled several weeks later, 235 homes in the town of Los Alamos had been destroyed and 47,650 acres of land had been burned. Hundreds of firefighters helped suppress the fire and rehabilitate the burned hillsides. June The western United States from Canada to Mexico continued to experience warm and dry weather. Throughout the month the trend continued and temperatures rose. Fuel moisture in the vegetation dropped to unusually low levels. Drought conditions were reported in several states including Arizona, New Mexico, southern California, and portions of Nevada, Idaho, Utah, western Wyoming and Montana. Very high to extreme fire danger indices were reported in nearly every western state. The national preparedness level was set at Level II for wildfire suppression. July Conditions were extreme. Lightning caused fires erupted in Nevada, Idaho, Colorado, Wyoming and Montana. Weather systems spun off winds generated by the fires, starting new fires. On July 15th, the national preparedness level was raised to Level III in response to the large wildland fires burning in the West.
On July 24th, all 11 western states and Texas, were managing many large fires. They were competing for crews of firefighters, aircraft, equipment, supplies, and overhead personnel. Dozens of new fires were being reported every day, while crews were struggling to contain those underway. Long-term weather forecasts showed no relief. The national preparedness level was raised to Level IV. All eight C-130 Modular Airborne Firefighting Systems aircraft were activated on July 26th to help suppress fires.
After four days, the National Interagency Fire Center declared preparedness Level V, the highest possible, on July 28th. NIFC began implementing strategies to address this serious situation. More than 20,000 firefighters were working to contain large fires or extinguish new starts with initial attack. Federal fire resources, from crews to aircraft to overhead personnel, were stretched to the limit. Military assistance was requested in late July. August Every day dozens of new or holdover large wildland fires were being reported. Initial attack forces were trying to respond to hundreds of new fires sparked by dry lightning storms. Most of the new starts were unstaffed as managers struggled to protect entire communities and hundreds of homes threatened by fires in Montana, Idaho, and in other western states. Because of the very dry fuels, hot weather and gusty winds many of the fires were very difficult to fight. The situation had become extreme. Firefighting resources were stretched to the limit and no relief was in sight from the weather. As a result, fire directors adopted a change in wildland fire management policy. The strategy for fighting the fires would be modified and adapted to fit the situation for the 2000 season.
The first priority of protecting human life remained a paramount concern and top priority. There would be no compromise on human lives. The second priority had been protection of property. This was changed to emphasis on initial attack. New fire starts required immediate suppression. As long as fires could be put out or controlled quickly, resources could be more effectively used. Fire fighters could be moved from existing large fires to insure that new fires were extinguished rapidly.
The third priority became protection of communities, critical natural resources, such as water supplies, and utilities. Since there were so many fires, managers had to make difficult choices regarding the allocation of limited resources. They looked carefully at the consequences of different choices and made decisions based on the best interest of the entire community. This meant that all structures could not be protected.
Multi-Agency Coordinating groups were establishing protection and suppression priorities in the Great Basin and Northern Rockies for fires in Idaho, Utah, Nevada and Montana. Four Area Command Teams were set up in Montana to help manage the state’s many large fires. All 16 Type 1 Incident Command Teams were assigned to fires. All 70 of the Type 1 crews were committed as well as most of the 409 smokejumpers. Of the 428 Type 2 crews, about 15 would become available each day only to be reassigned to high priority fires. Also, many states were supporting efforts with military reserve and National Guard personnel.
Military involvement fighting the fires was substantial. Within a week of the late July request military troops were on the fire lines assisting civilian fire fighters. A total of 3,000 troops participated. The following is a listing of battalions and fires.
U.S. Army 3rd Battalion, 16th Field Artillery, Fort Hood, TX, Burgdorf Junction, Payette National Forest, ID.
3rd Battalion, 5th Marines, Camp Pendleton, CA, Clear Creek Complex, Salmon-Challis National Forest, ID.
U.S. Army, 20th Engineers, Ft. Hood, TX, Upper Ninemile Complex, Lolo National Forest, MT.
3rd Battalion, 2nd Marines, Camp LeJeune, NC, replaced the 5th Marines on the Clear Creek Complex.
U.S. Army 3rd Battalion, 327th Infantry, Ft. Campbell, KY, Valley Complex, Bitterroot National Forest, MT.
U.S. Army 1st Battalion, 321st Field Artillery, Ft. Bragg, NC, Troy South Fire, Kootenai National Forest, MT.
Fire managers requested assistance from international partners, including Canada, Australia, New Zealand and Mexico. Canada quickly responded by sending three air tankers that were assigned to fires in Montana. More than 900 Canadians, Australians, New Zealanders and Mexicans supported US fire fighters in the form of smoke jumpers, hand crews, incident management team members, fire behavior specialists and ground support.
All told, more than 30,000 people, including civilian firefighters, state personnel, National Guard, Army, Marines, rural fire department personnel, and people from countries outside the United States were on fire lines or filling overhead positions. September As the season moved into September, three things happened: 1) the number of active fires peaked and began to decline; 2) fire activity increased in the southern area, especially Oklahoma and Texas; 3) the hot, dry weather eased in the northwest bringing cooler temperatures and higher humidity. Light to moderate rain showers began to fall in the central mountains of Idaho and in Montana.
The change in weather helped firefighters gain ground. They were able to contain more blazes than were being reported. Threats to communities from the fires diminished. Fire crews and support personnel were available for reassignment. Foreign support and military battalions began demobilizing. On September 6, after 40 days at preparedness Level V, national fire managers dropped the preparedness level to Level IV. October – November Firefighters continued to put out hot spots on the two largest fires of the season, the Valley Complex, Bitterroot National Forest, Montana and the Clear Creek Complex, Salmon-Challis National Forest, Idaho. Both fires were declared contained on October 4th and October 10th respectively. In Idaho and Montana, the emphasis had turned to rehabilitation of the charred land and protection of watersheds.
Southern and Southwestern states were still receiving new starts. These areas had not received any relief from the hot and dry weather. Most of the fires have been contained within two or three days. On November 4th a number of fires were started. The origin of the fires continue to be under investigation. The fires are concentrated in eastern Tennessee, southwestern North Carolina and southeastern Kentucky. Additional fires are located in the Shenandoah National Park. By November 6th, there were 16 fires in four states being reported on the national incident situation report.
As of November 6th, a total of 89,740 wildland fires have burned 7,208,642 acres across the United States. This is the second highest number of acres burned in the last 40 years. The ten-year fire season average, from 1990 to 1999, for numbers of fires is 106,393 and for acres burned is 3,786,411. Estimated fire suppression costs to October 12 have exceeded $1.065 billion. Fires claimed 852 structures during the fire season.
Rehabilitation costs spent on fires through October 18th, is $37.3 million. Rehabilitation Plans have been developed for 85 fires, over 78,000 acres have been seeded, 85 miles of stream beds have been protected, 25,498 acres have been weed treated and over 19,000 acres have intensive erosion control put in place. Rehabilitation will continue for several years depending on the severity of the burn and how well recovery has taken place.
Remarks on Prescribed Burning
Fire is an important natural tool for ecosystem management. It can reduce dense vegetation improving wildlife habitat and lessening the potential for large, wildfire disasters. Land managers are directed to prepare a prescribed fire/burn plan for every area of public land that can burn. Some areas require total suppression while others will benefit from a wildland fire. Those areas that will benefit from a fire can be treated by a prescribed fire.
Especially, for the moment, in the southern and southeastern regions of the United States prescribed fire activities will be carried out in the following weeks and months. In this case, fire signals on satellite images can be traced back to this kind of land management activities.
In the Prescribed Fire Position Paper of the Forest Protection Bureau by the Division of Forestry in Florida, prescribed fire activity is described as a land management application that is essential to the practice of forestry, management of wildlife, preservation of endangered plant and animal species, improvement of range conditions and reduction of wildfire damage in the wildland/urban interface areas. While there is general public and landowner concern with increased smoke, reduced air quality, and liability; the general public and landowners benefit significantly from the reduction of devastating wildfire, improved wildlife habitat and forage, preservation of endangered and threatened plant and animal species, and improved management of forest resources. The prospect of severe reductions in the utilization of this management tool is of major concern to Florida’s natural resource managers and conservationists due to the subsequent loss of derived public and private benefits. They suggest the need for legislative attention.