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) The following significant events were identified by Satellite Analysis Branch meteorologists and reviewed by the OSEI support team:
Clouds continued to cover much of the western states plagued by wildfires at the time of the NOAA-12 and 14 passes on the evening of 6-7 Sept. 2000 obscuring the heat signatures for the fires. A few heat signatures may be seen in southeast Texas, Louisiana.
NESDIS/OSEI NOAA-12 POES AVHRR HRPT satellite image, 6 September 2000
Heat signatures (red) and smoke (light blue) are visible from a number of fires burning
in southeastern Texas and Louisiana.
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 (7 September 2000) [conversion table] National Overview:
Preparedness Level IV
Eight new large fires were reported, six in the Southern area and two in the Rocky Mountain Area. Firefighters reached containment goals on six fires in the Southern, Southwest and Rocky Mountain Areas. Initial attack activity was heavy in the Southern Area and light elsewhere. Warmer and drier weather in Oregon, Idaho, Montana and Wyoming will revitalize large fire activity in those states. Scattered thunderstorms moving into eastern Texas and the Gulf Coast states may assist firefighters there. Very high to extreme fire indices were reported in Oregon, California, Idaho, Montana, Arizona, Utah, Wyoming, Nevada, Colorado, Kansas, Arkansas, Mississippi, Oklahoma and Texas.
Summary of Fire Activity Across The United States:
YesterdayYear to DateTen Year AverageFires 397 75,895 62,944 Acres Burned 41,757 6,656,217 2,977,356 Estimated Daily Cost $8 million
In the Northern Rocky Mountains, there are 20 fires over 1,000 acres. Favorable weather continues to moderate fire activity. Many fires are entering a monitoring stage prior to containment. Direct attack, rehab and mop-up continue on most fires.
Significant fire activity continues in the Southern area. The total number of fires decreased from 49 yesterday to 32 today, with 30 fires in Texas. There are 10 fires over 1000 acres.
In the Eastern Great Basin, there are 9 fires over 1,000 acres. Containment dates have been set for 2 fires.
The Rocky Mountain area has 3 large fires and containment is expected for 2 this week.
There is 1 fire over 1,000 acres reported in the Northern California area and containment is expected today.
There is one fire over 1,000 acres in the Western Great Basin and containment is at 90%.
Note: Access summary information for individual fires from the NIFC Incident Management Situation Report.
Resources and Statistics: Resources committed on September 6:
312 20 person crews, 132 helicopters, 4 Battalions military (500 each), 413 engines, 42 air tankers, 8 MAFFS-equipped military airplanes, 14,626 total personnel
Currently, there are 43 fires over 1,000 acres. The total number of acres burned this year is 223% of the ten-year average.
Other Information: Three Army battalions are assigned to fires in Montana. The 3rd Battalion, 2nd Marine Regiment is assigned to the Clear Creek fire in Idaho.
John Paul Prichett died September 3, 2000 as a result of complications from burns received while fighting fire in Mississippi on August 20, 2000. Mr. Prichett was an experienced firefighter who worked for the Mississippi Forestry Commission. Our condolences go out to Mr. Prichetts family and friends.
Weather Outlook: A RED FLAG WARNING IS POSTED IN EASTERN TEXAS AND SOUTHWEST LOUISIANA FOR POSSIBLE THUNDERSTORMS WITH GUSTY WINDS
South Texas and the Gulf Coast states will be warm, with an increasingly moist southerly flow bringing scattered thunderstorms during the afternoon and evening. High temperatures will be from the mid 80’s to the mid 90’s. Minimum relative humidities will be 40 to 50 percent inland and 50 to 60 percent along the coast. Winds will be east at 5 to 15 mph.
In the west, another series of troughs will move into the extreme northwest, while a ridge builds into the northern Rocky Mountains. As a result, it will be warmer and drier across much of Oregon, Idaho, Montana and Wyoming. Showers will move into northwest Washington late in the day. Further south, monsoon moisture will bring thunderstorms to parts of the southwest
High temperatures in the west will be in the 60’s and 70’s in the northern Rockies, in the 70’s and 80’s at lower elevations and in the 90’s to 100 in desert areas. Minimum humidities will range from the mid teens to the mid 30’s, with some single digit readings in the warmest southern deserts. Winds will be west to southwest at 10 to 15 mph.
National Interagency Fire Center (NIFC)
NIFC Wildland Fire Update (7 September 2000) [conversion table]
Hundreds of new fires were reported from states in the Southeast yesterday, with Texas experiencing most of the activity. There are currently 27 large fires burning throughout the state of Texas where hot and dry conditions are expected to continue today. Some relief is in sight however, as a storm system moves inland from the Gulf of Mexico during the next two days.
Wet and cool weather will be replaced by warm and dry conditions throughout most of the West today, which could cause a temporary increase in uncontained large fires. This short-term high pressure system is expected to give way to another series of storms throughout the Northwest, northern Idaho and western Montana tomorrow.
To date this year, 75,895 fires have burned 6,656,217 acres. The ten-year averages for September 6 are 62,944 fires burning 2,977,356 acres. See year-to-date statistics below for comparisons to previous years.
There are currently 66 fires burning in California, Idaho, Mississippi, Montana, Nebraska, Nevada, South Dakota, Texas, and Wyoming.
Large Wildland Fires in the United States, 7 September 2000.
6 September 2000Number of Wildland FiresArea burnt
Acresten year average 62,1072,954,953200075,0896,602,499 1999 70,839 4,416,506 1998 62,253 2,089,473 1997 51,379 2,726,004 199686,7385,822,036 1995 63,848 1,665,097 1994 58,626 3,315,444 1993 46,885 1,617,826 1992 70,558 1,564,862 1991 57,137 2,033,755 1990 56,087 4,389,331 1989 45,389 1,451,991 198868,0993,657,801
NIFC Wildland Fire Potential Assessment (10 August – 7 September 2000): ALASKA – Potential: Normal to below normal. Temperatures have been below normal and precipitation has been normal for the last four to six weeks. Fine fuels are green and fire activity should be minimal. Medium-range forecasts call for below normal temperatures. NORTHWEST Potential: Normal to above normal. Temperatures have been above normal and precipitation has been below normal in the area for the past month. Live fuel moistures are at or slightly below average in most areas and have been measured at 80% in central Oregon to 140% in western Washington. 1000 hour dead fuel moistures have been normal in the west and slightly below normal in the eastern portions. Measurements range from 21% in western Washington to 6% in southwestern Oregon. The area hasnt had any large timber fires yet as grasses are still green at the higher elevations. The Palmer Drought Index (PDI) shows extreme and severe drought through much of eastern Washington and Oregon. The long-range weather forecast calls for above normal temperatures. CALIFORNIA – Potential: Above normal. Temperatures have been above normal and precipitation has been below normal for the last 4 to 6 weeks. Live fuel moistures in the north are on the decline at 80% and in the south are being measured at 70%. 1000 hour fuel moisture is around 10 to 12% which is slightly below average. Areas east of the Pacific Coast Range are indicating above normal potential for large fire growth. PDI indicates moderate drought in the north and severe and extreme drought in the central and southern areas. Long- range forecasts calls for above normal temperature and below normal precipitation for central California. NORTHERN ROCKIES – Potential: Above normal. Precipitation has been below normal in much of the area and temperatures have been above normal. Live fuel moisture is ranging from 70% in sagebrush at lower elevations to 125% in conifer species at higher elevations. 1000 hour fuel moisture is 7 to 15% in the east and 6 to 12% in the west but higher in parts of northern Idaho (15 to 25%). Expect large fire activity to continue until sufficient moisture is received. PDI indicates severe and moderate drought conditions in Montana and south Idaho. Long-range weather forecasts call for above normal temperatures. GREAT BASIN – Potential: 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 45 to 112% in Nevada and 60 to 200% in the Eastern Great Basin. Fires have been exhibiting rapid rates of spread and 10 to 15 foot flame lengths in sagebrush fuels. The PDI indicates that the entire region is in severe and extreme drought conditions. Long-range weather predicts above normal temperatures for the period. Precipitation is forecasted to be above normal in southeastern Utah and below normal for southwestern Nevada. SOUTHWEST – Potential: Normal to above normal. Temperatures have been normal and precipitation has been below normal. The monsoon flow from Mexico was less than normal for July and there are no indications at this time that it will strengthen. Live fuel moisture readings are lower than normal in central and northern Arizona where it is at 55 to 95% and normal, at 75 to 120%, in the rest of the area. 1000 hour fuel moisture levels are normal to above normal at 6 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: Above normal. Temperatures were normal to above normal and precipitation was below 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 and continued large fire growth is anticipated. PDI indicates moderate and severe drought in most of the area except for southern Wyoming, where it is extreme. The long-range forecast calls for above normal precipitation for Colorado. EASTERN – Potential: Normal. Temperatures and precipitation have been normal through much of the area except above normal in the New England states. Live fuel moisture has been measured at 125% and above in Jack Pine needles. 1000 hour fuel moisture average values are between 20 to 35% and are currently being measured at 21 to 30%. The blow down timber area of the Boundary Waters Canoe Area Wilderness continues to be of concern due to the large fuel bed the wind event created. The PDI indicates that some of the northeastern Minnesota and northeastern Michigan continues to be in a moderate drought. Long-range climate forecasts call for below normal temperatures in the central Plains of the United States. SOUTHERN – Potential: Normal to above normal. Temperatures have been normal and precipitation has been normal to below normal. Live fuel moisture is being measured from 70 to 110% in Alabama and Texas and 130 to 160% in the rest of the area. 1000 hour dead fuel moisture is at 16 to 30%. Periodic rain showers have brought much needed drought relief and have mitigated fire danger in much of the area. The Palmer Drought Index 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, 10 August – 7 September 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.