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) (15 September 2000)
The following significant events were identified by Satellite Analysis Branch meteorologists and reviewed by the OSEI support team:
With the exception of Idaho and New Mexico, few heat signatures have been detected in the western states by the satellite sensors. Cooler weather, higher humidity, and rain and/or snow in some areas over the past several days may have reduced the heat signatures from existing hotspots below the level detectable by the satellites. The National Interagency Fire Center reports 16 fires in Arizona, Idaho, California, Florida, Montana, and Wyoming.
NESDIS/OSEI NOAA-12 AVHRR HRPT satellite image, 14 September 2000
Several heat signatures are visible in Idaho and eastern Oregon. These may be hotspots from the
NESDIS/OSEI NOAA-12 AVHRR HRPT satellite image, 14 September 2000
Several heat signatures are visible in southern New Mexico. These appear to be heat signatures
from fires but have not been verified via the National Interagency Fire Center list.
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.
Fire and Aviation Management Morning Report (17 September 2000) [conversion table] National Overview:
Preparedness Level III
Five new large fires were reported, four in the Southern Area and one in the Northern Rockies Area. Crews reached containment goals (work necessary to stop the fires spread) in Southern California, Eastern Great Basin and Rocky Mountain Areas. Initial attack activity was moderate in the Southern Area and light elsewhere. A trough moving through the Northern Rockies will bring showers and thunderstorms to Idaho, Montana, western Wyoming and northern Utah. Very high to extreme fire indices were reported in California, Idaho, Utah, Wyoming, Nevada, Montana, Arizona, New Mexico, Colorado, Kansas, Arkansas, Texas and Oklahoma.
The Southern California area has one fire over 1,000 acres. The 11,080 Harris fire in Santa Barbara County threatens a national defense installation and residences. It is 80% contained.
The Southern area has one fire over 1,000 acres.
In the Northern Rocky Mountains, there are 5 fires over 1,000 acres. Rehabilitation (the activities necessary to repair the damage or disturbance by the wildfire) and demobilization (the release of resources from an incident in accordance with the incident plan) activities are occurring on most fires.
In the Eastern Great Basin, there are 4 fires over 1,000 acres. Three of the four fires are at 70% or greater containment with no estimated containment on the fourth.
The Southwest has had an increase in fire activity with 2 fires over 1,000 acres.
There are no fires over 1,000 acres in the Rocky Mountain, Northwest, Northern California and Western Great Basin areas.
Note: Access summary information for individual fires from the NIFC Incident Management Situation Report.
Resources and Statistics: Resources committed on September 17:
117 20 person crews, 69 helicopters, 1 Battalion military (500 each), 326 engines, 10 air tankers and 5,600 total personnel. Currently, there are 13 fires over 1,000 acres. The total number of acres burned this year is 215% of the ten-year average.
Other Information: The 3rd Battalion, 2nd Marine Regiment is assigned to the Clear Creek fire in Idaho.
Weather Outlook[conversion table]: A RED FLAG WARNING IS POSTED FOR THE MOUNTAINS OF NORTHERN UTAH FOR RECORD HIGH TEMPERATURES, LOW HUMIDITIES, STRONG SOUTHWEST WINDS, AND HIGH HAINES INDEX.
A RED FLAG WARNING IS POSTED FOR PARTS OF WESTERN WYOMING FOR LOW HUMIDITIES, HIGH TEMPERATURES AND STRONG GUSTY WINDS.
A RED FLAG WARNING IS POSTED FOR NORTHERN AND CENTRAL ALABAMA FOR LOW HUMIDITIES.
A FIRE WEATHER WATCH IS POSTED FOR EASTERN AND SOUTHERN UTAH FOR STRONG SOUTHWEST WINDS, HIGH TEMPERATURES AND LOW HUMIDITIES
A FIRE WEATHER WATCH IS POSTED FOR PARTS OF EASTERN UTAH AND NORTHWEST COLORADO FOR STRONG WINDS, DRY THUNDERSTORMS, LOW HUMIDITIES, HIGH TEMPERATURES AND HIGH HAINES INDEX.
Across Oklahoma, Texas and the Gulf Coast states a high pressure aloft and at the surface will keep the region very dry. High temperatures in Oklahoma, South Texas and the Gulf Coast states will range from the upper 70’s to the lower 90’s. Minimum afternoon humidities will be 20 to 30 percent inland and 30 to 45 percent along the immediate coast. Winds will be northeast to east at 10 to 15 mph.
A trough will move through the Northern Rockies which will bring some showers and thunderstorms to Idaho, Montana, western Wyoming, and northern Utah. Conditions will be dry behind the trough in Washington and Oregon. Utah, southern Wyoming, and Colorado will be warm, windy and dry ahead of the trough. The rest of the Southwest will be dry.
High temperatures in the west will range from the 70’s and 80’s in the north to the 90’s and 100’s in the south. Minimum humidities will generally be in the teens through the 30’s with some single digits in the driest area in the south. Winds across the Pacific Northwest will be out of the northwest from 10 to 15 mph. Parts of Utah, Wyoming and Colorado will have winds out of the southwest at 15 to 25 mph, with gusts to 30 mph. The Southwest will have upslope, up valley, or southwest winds less than 15 mph.
National Interagency Fire Center (NIFC)
NIFC Wildland Fire Update (17 September 2000) [conversion table]
Wildland fire activity increased in several areas yesterday, and the weather is expected to cause intense burning conditions in some states in the West and South today. Extreme weather conditions are forecast for most of Utah, western Wyoming and central Alabama for high temperatures, low humidity and strong winds. Oklahoma continues to experience intense wildland fire activity with four new large fires reported yesterday, one of which was caused from an escaped hay bale fire. New fires were also reported in Texas where conditions remain extreme. The Lytton Springs fire 40 miles from Austin, Texas, burned one residence and is threatening four others. The Eldorado fire near Boulder, Colorado, caused evacuations of 100 homes, and is currently only five percent contained. To date this year, 77,654 fires have burned 6,675,588 acres. The ten-year averages for September 17 are 65,328 fires burning 3,109,412 acres. See year-to-date statistics for comparisons to previous years. There are currently 27 fires burning in Arizona, California, Colorado, Idaho, Montana, New Mexico, Oklahoma, Texas and Wyoming.
Large Wildland Fires in the United States, 15 September 2000.
17 September 2000Number of Wildland FiresArea burnt
Acresten year average 65,3283,109,415200077,6546,675,588 1999 73,465 4,675,242 1998 66,063 2,174,905 1997 52,737 2,749,945 199689,4915,937,170 1995 67,136 1,718,386 1994 60,229 3,515,526 1993 48,866 1,634,290 1992 78,260 1,904,854 1991 58,954 2,228,815 1990 58,076 4,555,016 1989 46,115 1,464,889 198869,0994,140,542
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.