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.
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.
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.
GeoMAC Wildland Fire Support The GeoMAC (Geospatial Multi-Agency Coordination Group) team has produced an internet based mapping application which allows firefighting coordination centers and incident command teams to access online maps of current fire locations and perimeters. Fire perimeter data is updated daily based upon input from incident intelligence sources, GPS data, IR imagery from fixed wing and satellite platforms. The fire maps also have relational databases in which the user can display information on individual fires such as name of the fire, current acreage and other fire status information. Additional data layers including fuel types, aircraft hazard maps, links to remote weather station data and other critical fire analysis information are currently being added to the GeoMAC application.
An example of GeoMAC Wildfire Information on forest fires in Idaho and Montana.
The right image shows a screen shot about the fire size at the Clear Creek Complex (see below), the biggest wildfire in Idaho.
Fire and Aviation Management Morning Report (17 October 2000) [conversion table] National Overview:
Preparedness Level I
Initial attack activity was light throughout the nation. No new large fires were reported to the National Interagency Coordination Center. Very high to extreme fire indices were reported in Oklahoma.
YesterdayYear to DateTen Year AverageFires 0 83,311 67,765 Acres Burned 0 6,912,243 3,153,769 Estimated Daily Cost 0
Burned Area Emergency Rehabilitation Summary as of 11 October 2000
287,500 Acres Severely Burned 82 Rehabilitation Plans Costs: $36 million 4,550 acres mulched 21,700 acres weed treated Over 78,000 acres seeded Over 1000 miles of road drainage protection 80 miles of stream protection Over 19,000 acres of intensive erosion control 110 miles of fence construction and reconstruction
Note: Access summary information for individual fires from the NIFC Incident Management Situation Report.
Resources and Statistics: Resources committed on 16 October 2000:
3 20 person crews, 1 helicopter, 2 engines, and 87 total personnel. A total of 32 heavy air tankers are available across the country.
Weather Outlook (17 October 2000)[conversion table] A RED FLAG WARNING IS POSTED FOR PORTIONS OF INLAND CENTRAL FLORIDA FOR LOW RELATIVE HUMIDITY.
A FIRE WEATHER WATCH IS POSTED FOR NORTH FLORIDA INCLUDING THE COASTAL COUNTIES OF THE EAST AND WEST COAST FOR LOW RELATIVE HUMIDITY.
In Southern California a ridge aloft will bring sunny and dry weather to the region. High temperatures will range from the 60’s to 70’s in the mountains and along the coast, and to the lower 90’s in the warmest deserts. Afternoon relative humidity will be 10 to 20 percent in the deserts and 20 to 40 percent elsewhere. Winds will be southeast to southwest 5 to 15 mph over the mountains and in the deserts, and 10 to 15 mph along the coast.
In Florida high pressure will weaken as a weak cold front pushes across the north bringing increased clouds over the area. Temperatures will be in the 80’s. Relative humidity will be 30 to 40 percent in the north and 35 to 50 percent in the southern areas. Winds will be northeast at 5 to 15 mph.
National Interagency Fire Center (NIFC) NIFC Wildland Fire Update (17 October 2000) [conversion table]
During the past week a few large fires were reported from Texas, Oklahoma and Minnesota, otherwise wildland fire activity has been minimal. Extreme fire conditions continue to be reported from Oklahoma, however, where a firefighter suffered from first and second degree burns when responding to a fire late last week.
NIFC Wildland Fire Potential Assessment (5 October – 2 November 2000): ALASKA – Potential: Below normal. Temperatures have been below normal and precipitation has been above normal for the last four to six weeks. Nighttime temperatures are routinely falling below freezing in the Interior. The 1000 hour and live fuel moisture levels are normal for this time of year. Typical October fire occurrence is five fires for .1 acre. NORTHWEST Potential: Normal to above normal. Temperatures have been normal and precipitation has been below normal in the area for the past month. Live fuel moistures are below average in all areas and have been measured at 59% to 148% in Washington and 53% to 124% in Oregon. 1000-hour dead fuel moistures are also below average for this time of the year. Measurements range from 8% to 19% in Washington and 5% to 16 % in Oregon. The Energy Release Component (ERC) is showing well above average for southeastern Oregon, average for northwestern Washington and above average for the rest of the area. Palmer Drought Index (PDI) indicates extreme to severe drought conditions in eastern Washington and Oregon. The long-range weather forecast calls for average to above normal temperatures and below average precipitation for most of the area. CALIFORNIA – Potential: Normal to above normal. Temperatures and precipitation have been normal for Northern California. Live fuel moistures have reached their critical levels and are now mostly dormant. 1000-hour fuel moisture in most of the state is around 8% to 15%, which is slightly below average. PDI indicates normal conditions in the north except east of the Sierra range where severe drought conditions persist. Long range forecast calls for normal temperatures and slightly below normal precipitation for Northern California. NORTHERN ROCKIES – Potential: Above normal. Precipitation has been below normal in much of the area and temperatures have been above normal. Live fuel moistures are continuing to experience drought induced stress. Rainfall was received at the first of the month, but the area still lags behind in the year to date precipitation. The PDI indicates extreme and severe drought conditions continue to exist in most of Montana and Idaho. Long-range weather forecasts call for slightly above normal precipitation for southeast Montana and normal conditions for the rest of the area. GREAT BASIN – Potential: Normal. Temperatures have been above normal during the past month while precipitation has been below normal through the area. Live fuel moisture is ranging from 73% to 143% in Nevada and 30% to 120% in the Eastern Great Basin. 1000-hour fuel moisture is averaging 5% to 9% in Nevada and from 6% to 18% in the Eastern Great Basin. Due to precipitation early in the month, shorter days and increased nighttime relative humidity has moderated the fire danger. The PDI indicates that most of the region is still in severe and extreme drought conditions except for southern Nevada. Long-range weather predicts normal to above normal temperatures and below normal precipitation. SOUTHWEST – Potential: Normal. Temperatures have been normal and precipitation has been normal to a little below normal in eastern New Mexico. PDI shows drought conditions continuing though recent precipitation has lessened the fire danger. The long-range outlook indicates above normal temperatures and slightly below normal precipitation. ROCKY MOUNTAIN – Potential: Normal to above normal. Temperatures were normal to above normal and precipitation was normal to below normal for the last four to six weeks. Live fuel samples are well below normal for much of the area in the conifer and oakbrush fuels due to lack of long duration precipitation. 1000-hour fuel moisture is around 6% to 10 % in the north-central portions of Wyoming and 11% to 15% in the rest of the area. The potential for short duration large fire occurrence remains high for the period. PDI indicates severe and moderate drought in most of the area. The long-range forecast calls for above normal temperatures and below normal precipitation for most of the area. EASTERN – Potential: Normal. Temperatures have been below normal in Indiana, Minnesota and the Lower Peninsula of Michigan. Above normal temperatures were observed for the rest of the area. Precipitation has been above normal through much of the area for the last month. The 1000-hour fuels are currently ranging from 18% to 30% which is slightly below average for this time of year. The PDI indicates that most areas are near normal or wetter than normal. Potential still exists for large fire growth in the southern part of the area due to continuing drought conditions. Long-range climate forecasts call for normal temperatures except for the Great Lakes, which is predicted to be below normal. The Eastern Seaboard is predicted to have above normal precipitation this month and normal rainfall for the rest of the area. SOUTHERN – Potential: Normal to above normal. Temperatures have been below normal in Kentucky and Virginia and normal elsewhere. Precipitation has been below normal in Texas, Oklahoma and Louisiana. The PDI shows large portions of Texas, Mississippi, and Alabama to be in severe to extreme drought conditions. The long-range outlook is calling for above normal temperatures and normal precipitation for the area.
Temperatures and precipitation reflect conditions over the past four to six weeks. The long-range forecast is for the next 30 days. Above and below normal is indicated above in the narrative, areas not mentioned fall in the climatological category which means there are equal chances of being below normal (33.3%), normal (33.3%) or above normal (33.3%)
Map describing the wildland fire potential, 5 October – 2 November 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)
The Clear Creek Complex in Idaho (Salmon-Challis National Forest, 10 October 2000) At day 87 and still counting, the Clear Creek Fire is now 90 percent contained, and fire managers estimate that by November 1 the fire should be fully controlled. Carr’s Type II team turned the fire over to local Forest management this week, and most resources are being demobed. The Clear fire camp has been vacated, and things are winding down at a rapid pace. Four crews will remain on the fire to complete mop-up and rehabilitation. They will be housed at the Care Center in Salmon and at the Moyer Housing site in Cobalt. Suppression rehab work is continuing after being put on hold for a day waiting for the soils to dry from the rain showers last weekend. Rehab is about 75 percent completed, and cataloging of additional rehab sites is ongoing. This work will continue until late fall, with an emphasis on preparing the land to withstand the effects of spring runoff. Some of the work that has been occurring or that will start soon includes the planting of riparian species along lower Panther Creek, spreading grass and forb seeds, cross-slope felling and placing of trees in steep areas, laying straw wattles to intercept silt and fine debris, and clearing culverts and ditches.
A view from the helicopter over parts of the burned area from the Clear Creek Complex.
The fire base camp one month ago.
The Clear Creek Fire burned in a mosaic pattern, and the varying intensity of the fire is obvious. About 5 percent of the area, much of it in watersheds and elk winter range, shows high intensity burn. About 25 percent of the area burned with moderate intensity, and another 70 percent of the 216,000 acres burned either at low intensity or not at all.
The objective of fire rehabilitation is to mitigate suppression damage of wildfire and restore disturbed areas to as near pre-fire conditions as possible. Damaged meadows and riparian areas and steep slopes with high erosion potential should be prioritized to receive immediate rehabilitation. Several medium-sized track-mounted or rubber-tired excavators and hand crews will be needed to accomplish the rehabilitation work.
General rehabilitation includes: clearing drainage ditches and lead-out ditches of slash and debris, reshaping damaged segments of road near log decks, and watering and grading the road to repair the surface damaged by heavy equipment and excessive traffic.
Standard treatment for rehabilitation of safety zones includes: pulling in topsoil from berms around the perimeter of the safety zone; spreading the recovered topsoil over the disturbed area; distributing slash and limbs and tops from felled and culled trees over the topsoil; and piling and burning excess slash.
As part of fire protection efforts during the Clear Creek fire, a fuel break was constructed along the Salmon River Ridge road above the municipal watershed for the City of Salmon. The work created a large amount of felled trees and high stumps that hamper the effectiveness of the fuel break and impede suppression rehabilitation efforts. Therefore, the high stumps will be crushed or cut flush to the ground and most of the felled trees will be removed from along the fuel break by the equipment performing suppression rehabilitation work.
Left: Hydrologists, geologists and forester discuss the procedure of a creek rehabilitation.
Bulldozer went through the stream and destroyed the natural stream.
Right: On a very steep slope a bulldozer built a fireline. This area is very sensitive, due to the very high erosion risk.
Left: The topsoil from berms around the perimeter of a safety zone have to be pulled back.
Right: A former forest road, which was rebuilt and re-seeded (front: green and brown), was again destroyed by a dozerline (back: white).
Dozerline rehabilitation may be delayed in some areas until salvageable timber is removed under the authority of a timber sale contract. Many areas impacted by dozerline have not yet been inventoried because fire is still actively burning. Specialized equipment and techniques may be necessary to rehabilitate some dozerline. A site-specific plan for each area, similar to the one written for the Mackinaw Creek restoration, will be completed and agreed upon prior to rehabilitation. Due to the number of miles of dozer and hand line that may require suppression rehabilitation and impending winter weather, the Incident Management Team and the Forest may not be able to complete rehabilitation measures this year, except on the highest priority areas.
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.