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.
Operational Significant Event Imagery (OSEI) (19 September 2000)
The following significant events were identified by Satellite Analysis Branch meteorologists and reviewed by the OSEI support team:
NESDIS/OSEI NOAA-12 AVHRR HRPT satellite image, 19 September 2000
left: Several heat signatures are visible in northern Idaho, northern Oregon, and eastern Washington.
right: Several heat signatures and smoke plumes are visible from fires burning in Arkansas, Louisiana,
Missouri Mississippi, Kansas, Oklahoma, Tennessee. Some may be controlled burns.
NESDIS/OSEI NOAA-12 AVHRR HRPT satellite image, 19 September 2000
left: Heat signatures and dense smoke are visible from the 4,000 acre Arbuckle Complex and 2,500 acre
Oakcliff fires in Oklahoma. Numerous other heat signatures from fires are visible in Kansas, Oklahoma, and Texas.
center: The heat signature and smoke plume are visible from the 800 acre Concow fire in northern California.
right: The Sierra and Bloodgood fires burning in the Gila National Forest have been renamed the Bloodgood
Complex. Heat signatures from these fires are visible in this NOAA-14 image.
The BLM – Alaska Fire Service Initial Attack Management System (IAMS) is suite of computer applications developed by BLM/Fire to aid dispatchers and fire managers. IAMS Maps is one of these applications and provides graphical representation of various kinds of geographic data. Maps has been modified to produce output to a Web site to allow internet access to the data that IAMS stores. Dynamic data such as lightning (available May – September), fires, etc. are updated at the homepage of the BLM – Alaska Fire Service (select Maps / AFS IAMS Maps Viewer) every 15 minutes during the fire season.
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, the biggest wildfire in Idaho.
Additional Information to the Clear Creek Complex (18 September 2000) The Clear Creek Complex, 12 miles west of Salmon, is the largest fire in Idaho, and has an area 206,379 acres. It is to 85% contained. The estimated date of full containment on the Clear Creek Fire is aprrox. 30 September 2000. Currently, 1585 people, 14 helicopters, 18 engines, 7 dozers are assigned to the fire. Fire behavior on the Clear Creek fire was minimal Sunday due to the cooler temperatures and higher humidity than Saturday.
A view from the helicopter over parts of the burned area from the Clear Creek Complex.
The fire base camp two weeks ago.
Fire and Aviation Management Morning Report (20 September 2000) [conversion table] National Overview:
Preparedness Level III
Eleven new large fires were reported, one in the Rocky Mountain Area, one in Northern California and nine in the Southern Area. Crews reached containment goals on seven large fires. Initial attack activity was moderate in the Southern Area and light elsewhere. Very high to extreme fire indices were reported in Oregon, California, Idaho, Utah, Nevada, Montana, Arizona, Colorado, Kansas, Arkansas, Texas, Alabama, and Oklahoma. There are red flag warnings for 3 states today.
The Southern area had an increase in activity with 8 fires over 1,000 acres, primarily on State lands. Fires are being driven by high winds. Evacuations have taken place in Texas and Oklahoma. Fifty primary structures were lost in Oklahoma with many more threatened.
The Rocky Mountain area also had an increase in fire activity with 5 fires now over 1,000 acres. Activity is across the region from Nebraska to Wyoming.
In the Northern Rocky Mountains, continued progress is being made with a reduction to 5 fires over 1,000 acres.
In Northern California the new 800 acre Concow fire is currently threatening structures.
Note: Access summary information for individual fires from the NIFC Incident Management Situation Report.
Resources and Statistics: Resources committed on 20 September 2000:
179 20 person crews, 75 helicopters, 1 Battalion military (500 each), 531 engines, 10 air tankers and 7,892 total personnel. Currently, there are 22 fires over 1,000 acres, an increase of one fire from yesterday. The total number of acres burned this year is 220% of the ten-year average. The Southern area showed a sizable increased activity with 4 new fires over 1,000 acres and total 22 fires. Evacuations have taken place in Texas and Oklahoma. Several structures were lost in Okalahoma. The Eldorado fire in Colorado was contained (work necessary to stop the spread of the fire has been completed). 68 International personnel from three countries continue to support firefighting efforts: Australia 55, New Zealand 10, and Mexico 2 as of 18 September 2000. At one time there were over 800 international personnel helping us.
Other Information: The 3rd Battalion, 2nd Marine Regiment is assigned to the Clear Creek fire in Idaho.
Weather Outlook (21 September 2000)[conversion table]: A FIRE WEATHER WATCH IS POSTED FOR ALL OF MISSISSIPPI FOR LOW FUEL MOISTURE.
A FIRE WEATHER WATCH IS POSTED FOR NORTHWEST ARIZONA AND SOUTHERN NEVADA FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY.
Across Oklahoma, Texas and the Gulf Coast States, a weak cold front will stall in central Texas and Louisiana as moisture continues to move northward out of the Gulf of Mexico. This will bring heavy rains to the coastal areas and isolated rains toward the Rio Grande River. High temperatures will range from the 70’s to 80’s north of the cold front and 80’s to 90’s to the south. Minimum afternoon humidity will be 30 to 40 percent inland and 45 to 60 percent along the immediate coast. Winds will be south to southeast 10 to 15 mph ahead of the cold front and northwest 10 to 15 mph behind it.
Across the west coast a strong, cold upper level trough will dip southward through the Northern Rockies and the Great Basin. As a result, Oregon and California will have mostly sunny skies, cooler temperatures and locally breezy northeast winds. High temperatures in Oregon and Washington will be into the 60’s and 70’s, northern California will have temperatures into the 80’s and 90’s. Inland California’s afternoon relative humidity will lower into the 15 to 30 percent range and inland pacific northwest’s will be slightly higher. The Coastal areas will have relative humidity from 40 to 60 percent. Winds will be north to northeast 10 to 20 mph.
National Interagency Fire Center (NIFC)
NIFC Wildland Fire Update (20 September 2000) [conversion table]
Eleven new large fires were reported in the last 24 hours, nine of them in the Southern Area, one in the Rocky Mountains and one in California. Crews reached containment goals on seven large fires. Increased moisture will bring a chance of showers and thunderstorms along the gulf coast. Critical fire weather conditions exist from central California to northwest Oregon, with temperatures over 100 degrees in some locations. To date this year, 78,895 fires have burned 6,906,617 acres. The ten-year averages for September 20 are 65,632 fires burning 3,117,531 acres. There are currently 34 fires burning in Alabama, California, Colorado, Idaho, Montana, Nebraska, New Mexico, Oklahoma, Texas, and Wyoming.
Large Wildland Fires in the United States, 20 September 2000.
20 September 2000Number of Wildland FiresArea burnt
Acresten year average 65,6323,117,531200078,8956,906,617 1999 73,746 4,742,842 1998 66,500 2,176,039 1997 53,299 2,753,924 199689,4955,938,790 1995 67,782 1,720,404 1994 60,473 3,520,118 1993 49,3847 1,635,418 1992 78,195 1,900,749 1991 58,954 2,228,815 1990 58,494 4,558,210 1989 46,393 1,466,147 198869,3144,175,014
NIFC Wildland Fire Potential Assessment (7 September 2000 – 5 October 2000): ALASKA – Potential: Below normal. Temperatures have been below normal and precipitation has been above normal for the last four to six weeks. August temperatures were the coolest ever recorded for most of the Interior. The Fire Potential Index is low and Fine Fuel Moisture Code is being measured as low and very low throughout the Interior. Shorter days and colder temperatures will continue the below normal fire activity in September. 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 close to average in areas and have been measured at 79% in northeastern Oregon to 161% in northwestern Washington. 1000-hour dead fuel moistures have also been mostly average for this time of the year. Measurements range from 21% in northwestern Washington to 8% in southeastern Oregon. The Energy Release Component (ERC) is being measured at or above average in the west and above average in the eastern portions of the area. PDI (Palmer Drought Index) indicates severe drought conditions in eastern Oregon and extreme drought in central Washington. The long-range weather forecast calls for above normal temperatures and below average precipitation for most of the area. CALIFORNIA – Potential: Above normal. Temperatures have been normal in the north and above normal in the south. Precipitation has been below normal for the last 4 to 6 weeks and the recent rains could provide only short-term relief. Live fuel moistures in the north are still at critical levels at about 70% in the north. Live fuel moistures are being measured at around 50% to 70% in the south and east and up to 100% in the west. 1000-hour fuel moisture in most of the state is around 6% to 10%, which is below average. Predicted Santa Ana winds could be a factor in the next month. PDI indicates normal conditions in the north and severe and extreme drought in the central and southern areas. Long range forecasts calls for above normal temperatures. 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 being measured from the 50% to 120% and 1000 hour fuel moistures are generally between 10% to 20 % in the area. Though recent storms in northern Idaho and western Montana have brought some relief to large fire growth, the PDI indicates extreme and severe drought conditions exists in much of the area. Long-range weather forecasts call for above normal temperatures and below normal precipitation in northwestern Idaho. GREAT BASIN – Potential: Normal to above 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 47% to 113% in Nevada and 51 to 170% in the Eastern Great Basin. 1000-hour fuel moisture is averaging 6% in Nevada and from 5% to 15% in the Eastern Great Basin. Cloudy skies, higher humidities and cooler temperatures have moderated fire conditions for the present. The PDI indicates that most of the region is in severe and extreme drought conditions except for southern Nevada. Long-range weather predicts normal to above normal temperatures and near normal precipitation. SOUTHWEST – Potential: Normal. Temperatures have been normal and precipitation has been normal to above normal. Live fuel moisture readings are normal in much of the area at 95% to 120%. 1000-hour fuel moisture levels are normal to above normal at 10% to 14% in Arizona and 10% to 18% in New Mexico. Palmer Drought Index (PDI) shows extreme drought conditions in Arizona and severe drought in central and western New Mexico. The long-range outlook indicates above normal temperatures and above normal precipitation for the next 30 days. ROCKY MOUNTAIN – Potential: Normal to above normal. Temperatures were below normal to above normal and precipitation was normal to above normal for the last four to six weeks. Live fuel samples are below normal for much of the area, ranging from 95% in ponderosa pine to 70% to 90% in pinyon pine and juniper fuels. 1000-hour fuel moisture is around 6% to 10 % in the west and 11% to 15% in the east, which is slightly below normal. Normal monsoon moisture did not move far enough north to provide relief from the dry conditions in Wyoming and eastern South Dakota so large fire growth is anticipated in those areas. PDI indicates severe and moderate drought in most of the area. The long-range forecast calls for normal precipitation for Colorado. EASTERN – Potential: Normal. Temperatures and precipitation have been normal through much of the area for the last month. The 1000-hour fuels are currently ranging from 18% to 25% which is average for this time of year. Potential for any significant activity should be limited to the southern tier states. The PDI indicates that most areas are near normal or wetter than normal. Long-range climate forecasts call for normal temperatures. Below normal precipitation is predicted for the Great Lakes and above normal for the Eastern Seaboard. SOUTHERN – Potential: Normal to above normal. Temperatures have been below normal in Kentucky and Virginia and normal elsewhere. Precipitation has been below normal in most of the southern tier states. Live fuel moisture is being measured as low as 30% to 50% in Texas and Louisiana and at 120% to 180% elsewhere. 1000 hour dead fuel moisture is at 12% in Louisiana and is averaging 18% through much of the rest of the area. The PDI shows large portions of Texas, Louisiana, Arkansas, Mississippi, Georgia, and Florida and all of Alabama to be in drought conditions. The long-range outlook is calling for normal temperatures and precipitation for most of 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, 7 September – 5 October 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 (September and September to November 2000)
(Source: National Weather Service)
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.