Forest Fires in the United States: 26 May 2000

Forest Fires in the United States

26 May 2000

New Mexico fire contained
The Los Alamos fire, which burned nearly 48,000 acres and destroyed more than 200 homes in northern New Mexico was 100 percent contained Wednesday evening. Despite containment, Forest Service officials fear the fire could flare up again during thunderstorms forecast for the Los Alamos area this week. There are still some fuels, which are prime to burn. Firefighters on Wednesday completed a 100-mile-long firebreak with a buffer strip up to 50 feet wide. More than 600 firefighters, including support staff, still were involved in fighting the blaze, which started May 4 as a controlled burn before winds whipped it out of control and into Los Alamos and its famous nuclear research laboratory. About 1,400 firefighters were working the fire at ist peak last week. If the fire doesn’t flare up again, probably it is expected to be extiguished by Sunday night.
Source: New Mexico fire contained (published by Environmental News Network, 25 May 2000)

Heat signatures (red) are visible from numerous fires burning in south Florida. Additional fires may be burning beneath the cloud cover.

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Fig. 1. NOAA-14 POES AVHRR HRPT multichannel color composite for Florida, 25 May 2000.
(Source: NOAA/OSEI).

Wildland Fire Update for the United States on 25 May 2000 (National Interagency Fire Center (NIFC))
The Cerro Grande fire near Los Alamos, New Mexico, was contained yesterday at 47,650 acres. New large fires were reported from Arizona, Florida and South Carolina as hot and dry conditions persist throughout the Southwest and Southeastern portions of the country. Very high to extreme fire conditions were reported from Arizona, New Mexico, Texas, Utah, Oklahoma, Colorado, California and Kansas. Florida also continues to experience extreme fire conditions as dry, hot weather persists throughout the state. The National Weather Service has posted a red flag warning and fire weather watch for gusty winds and low afternoon humidities for most of the state.

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.

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Fig. 2.-4. Fire Danger Forecast Maps of the United States and Alaska for 25 May (observation time) and 26 May 2000 (forecast).
(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.

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Fig. 5. Keetch-Byram Drought Index Map of the United States, 25 May 2000
(Source: Fire Behavior Research Work Unit, Missoula)

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.

Incident Management Situation Report (25 May 2000)
Current Situation:
New large fires were reported in Arizona, Florida, and South Carolina. Initial attack activity was moderate in the Southern Area and light elsewhere. Continued hot and dry conditions are forecast for both the Southern and the Southwest Areas. The National Interagency Coordination Center processed orders for radio equipment, engines, a caterer, and miscellaneous overhead. An Area Command Team (Edrington) was ordered to the Southwest Area for the Cerro Grande Complex. Very high to extreme fire indices were reported in Arizona, New Mexico, Utah, Texas, Oklahoma, Colorado, California, and Kansas.
A fire weather watch is posted in central florida for unstable air, gusty winds and low afternoon Relative humidities.
Florida will be partly cloudy with widely scattered afternoon and evening showers and thunderstorms. High temperatures will be 85 to 95. Winds will be southwest to west at 8 to 15 mph. Minimum afternoon relative humidities will be 35 to 50 percent.
North and central New Mexico and northern Arizona will be partly cloudy with scattered afternoon and evening thunderstorms. High temperatures will be in the 70’s and 80’s. Winds will be south to west at 15 to 25 mph. Minimum afternoon relative humidities will be 20 to 35 percent.
Southern Arizona and southern New Mexico will be mostly sunny. High temperatures will be from the 80’s to 105 in the deserts. Winds will be south to southwest at 15 to 25 mph. Minimum relative humidities will be 5 to 20 percent.
West Texas will be sunny with a few clouds and a chance of afternoon and evening thunderstorms in the northern part of the state. High temperatures will be from the lower 80’s to 105. Winds in the north will be east at 10 to 15 mph. In south Texas, winds will be south to southwest at 5 to 15 mph. Afternoon relative humidities will range from 5 to 30 percent.

Long-range, 30-day weather forecasts are predicting above-normal temperatures and below-normal precipitation for the southern tier of states from southern California to Florida and throughout the Midwest (see 30 and 90-day forecast maps).

Tab.1. Five-Year Wildland Fire Comparison Statistics Year-to-Date for the United States (25 May 2000)
(Source: National Interagency Fire Center (NIFC)

As of 05/25/00 Number of Wildland Fires Area burnt Acres Hectars 2000 40,475 1,045,472 423,087 1999 39,272 730,996 295,823 1998 21,027 392,520 158,847 1997 26,981 429,103 173,651 1996 55,155 1,467,534 593,889

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Fig. 6. 30 and 90-day temperature and precipitation forecast maps (June and June to August 2000)
(Source: National Weather Service, Boise, Idaho)

Remarks on Prescribed Burning
At this time of the year prescribed burning operations are conducted routinely.
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.

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