GFMC: Forest Fires in the United States, 11 September 2000
Forest Fires in the United States
11 September 2000
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 10 September 2000 (observation time) and 11 September 2000 (forecast)
(Source: Fire Behavior Research Work Unit, Missoula)
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, 10 September 2000
(Source: Fire Behavior Research Work Unit, Missoula)
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, 10 September 2000
(Source: Fire Behavior Research Work Unit, Missoula)
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 7-8 Sept. 2000 obscuring the heat signatures for the fires. Few heat signatures have been detected by the satellite sensors. Cooler weather, higher humidities, 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 50 large active fires.
NESDIS/OSEI NOAA-12 POES AVHRR HRPT satellite image, 18 August and 8 September 2000
Two images of the Idaho and western Montana area are provided. One is from 18 August 2000 when
numerous large heat signatures and dense smoke are visible.
The second image is from 08 September 2000 after several days of cooler temperatures, higher
humidities, and rain and/or snow in some areas. Only one heat
signature located in northern Idaho was detected by the NOAA-12 satellite. The National Interagency
Fire Center reports 6 active large fires in Idaho and 23 in Montana.
(Source: NESDIS/OSEI)
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.
IAMS image of active fires in Alaska, 11 September 2000
(Source: BLM – Alaska Fire Service)
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 (10 September 2000) [conversion table]
National Overview:
Preparedness Level IV
Two new large fires were reported in the Southern Area. Crews reached containment goals on four fires, three in the Southern Area and one in the Rocky Mountain area. Initial attack activity was light throughout the United States. Scattered showers can be expected across the Pacific Northwest and Northern Rockies due to another trough from the Pacific moving through the area. The high pressure ridge in the South will remain over Florida allowing some moisture to move across Texas and the coastal regions. Very high to extreme fire indices were reported in Oregon, California, Idaho, Montana, Wyoming, Arizona, New Mexico, Colorado, Kansas, Arkansas, Oklahoma and Texas.
Summary of Fire Activity Across The United States:
Yesterday Year to Date Ten Year Average Fires 69 76,661 63,465 Acres Burned 3,728 6,643,973 3,008,322 Estimated Daily Cost $6 million
Regional Summary:
- In the Northern Rocky Mountains, there are 12 fires over 1,000 acres compared to 18 fires two days ago. Four fires were contained yesterday. Many fires are entering a monitoring stage prior to containment. Scattered precipitation is expected throughout the area.
- Fire activity moderated in the Southern area. The total number of fires decreased from 49, four days ago to 11 today. Three fires were contained yesterday. There are 4 fires over 1000 acres. Precipitation remains in the weekend forecast.
- In the Eastern Great Basin, there are 6 fires over 1,000 acres compared to 9 two days ago. Containment of the Clear Creek Complex is set for September 30th.
- The Rocky Mountain area has 2 large fires. The 83,500 acre Jasper fire has been contained.
- There is one fire over 1,000 acres in the Northern California area and containment is at 95%. There are two fires over 1,000 acres in the Western Great Basin.
Note: Access summary information for individual fires from the NIFC Incident Management Situation Report.
Resources and Statistics:
Resources committed on 9 September:
213 20 person crews, 98 helicopters, 4 Battalions military (500 each), 289 engines, 42 air tankers 8 MAFFS-equipped military airplanes, 8,979 total personnel.
Currently, there are 28 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.
Weather Outlook:
FIRE WEATHER WATCH FOR THE MAJORITY OF CENTRAL AND EASTERN MONTANA, PARTS OF NORTHWEST SOUTH DAKOTA AND THE BIG HORN MOUNTAINS OF WYOMING FOR STRONG AND GUSTY WINDS.
In the West another Pacific trough will move across the Pacific Northwest and Northern Rockies, resulting in scattered showers for these areas. Further south dry air over the region will bring mostly sunny skies to the Southwest and Central Rockies.
High temperatures in the West will be in the mid 50s to mid 70s in the Northern Rockies and Intermountain West. The Southwest will have temperatures of 70 to 80 and 90 to 110 in the warmest deserts.
Minimum relative humidity will generally be in the mid teens to 30 percent with some single digits in the warmest southern deserts. Relative humidity of 45 to 60 percent can be expected in some locations of the North.
Winds will mostly be southwest to west at 10-20 mph. Expect west wind 20 to 30 mph with gusts to 40 mph across the Northern Plains and Central Rockies.
For the Southern area high pressure will remain over Florida and Georgia. This will continue to allow moisture and scattered thunderstorms to move into Texas and the coastal regions. High temperatures will be in the 80s to 90s with 100 expected near the Rio Grande. Minimum relative humidity will be 40 to 50 percent inland and 60 to 70 percent along the Gulf Coast. Winds will be east to south at 5-15 mph.
National Interagency Fire Center (NIFC)
NIFC Wildland Fire Update (10 September 2000) [conversion table]
Initial attack activity was light throughout the United States. Scattered showers are expected across the Pacific Northwest and Northern Rockies. The high pressure ridge in the South will remain over Florida allowing some moisture to move across Texas and the coastal regions. To date this year, 76,661 fires have burned 6,643,973 acres. The ten-year averages for September 10 are 63,465 fires burning 3,008,322 acres. See year-to-date statistics for comparisons to previous years. There are currently 29 fires burning in California, Idaho, Montana, Nebraska, Nevada, Texas, Oklahoma, Utah and Wyoming.
Large Wildland Fires in the United States, 7 September 2000.
(Source: NIFC)
NIFC Year-to-Date Statistics for the United States (10 September 2000) [conversion table]
As of
10 September 2000 Number of Wildland Fires Area burnt
Acres ten year average 63,306 3,000,729 2000 76,587 6,641,621 1999 71,158 4,448,401 1998 65,164 2,145,609 1997 51,957 2,729,695 1996 88,142 5,828,430 1995 64,647 1,702,616 1994 59,038 3,364,913 1993 47,603 1,652,267 1992 70,943 1,664,545 1991 57,808 2,075,622 1990 56,601 4,395,188 1989 45,602 1,459,214 1988 68,490 4,041,036
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
(Source: NIFC)
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.
Another report on nation-wide prescribed burning in the U.S.A. was published in International Forest Fire News No.19 (September 1998).
A set of photographic documents on prescribed burning techniques and objectives in the Southeast can be visited in our photo archive.
