Forest Fires in the United States: 30 May 2000
Forest Fires in the United States
30 May 2000
Wildland Fire Update for the United States on 26 May 2000 (National Interagency Fire Center (NIFC))
The national response level increased today as states across the southern portion of the country report increased activity. More than 200 new fires were reported yesterday, with six escaping to become large fires in Arizona, California, South Carolina and Florida. Nearly 1,900 firefighters are currently assigned to fires, mostly in the Southwest and Southeastern areas. They are supported by 90 engines, 38 helicopters, 25 airtankers and 773 support personnel. A fire weather watch is posted in northern New Mexico for gusty winds and low late afternoon relative
humidities. A fire weather watch is also posted in western Florida for low afternoon relative humidities.
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.
Fig. 1.-2. Fire Danger Forecast Maps of the United States for 29 May (observation time) and 30 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.
Fig. 3. Keetch-Byram Drought Index Map of the United States, 29 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 (28 May 2000)
Current Situation:
New large fires were reported in the Southwest, Southern, Eastern Great Basin, Northern Rockies, and Rocky Mountain Areas. Initial attack activity was heavy in Florida and most resources within the state are committed. Initial attack activity was moderate in the Southwest Area and light elsewhere. An Area Command Team (Harbour) has been ordered to manage new fires in northern Arizona. The National Interagency Coordination Center mobilized helicopters, infrared aircraft, a lead plane, caterers, shower units, radio equipment, crews, and miscellaneous overhead. Very high to extreme fire indices were reported in Arizona, New Mexico, Utah, California, Texas, Oklahoma, Colorado, Kansas, and Mississippi.
Outlook:
A red flag warning is posted in florida for low afternoon humidities
Northern Florida will be mostly sunny. In the south, it will be partly cloudy with a chance of scattered afternoon showers and thunderstorms during the afternoon hours. High temperatures will be in the 80’s on the coasts and in the 90’s in the interior. Winds will be southwest to west at 10 to 15 mph. Minimum relative humidities will range from 30 to 40 percent.
Arizona will be mostly sunny and hot. Temperatures will be in the mid 80’s in the mountains and up to 115 in the southern deserts. Winds will be southwest at 15 to 25 mph. Minimum relative humidities will be 5 to 15 percent.
New Mexico will be mostly sunny and hot. Isolated afternoon thunderstorms are forecast for the southern mountains. High temperatures will be from the mid 70’s in the mountains to around 100 in the southern deserts. Winds will be southwest to west at 10 to 25 mph. Minimum relative humidities will be 10 to 20 percent.
Southern Utah will be mostly sunny, windy and hot. High temperatures will be in the 90’s and mid 100’s. Winds will be southwest at 15 to 30 mph. Minimum humidities will be 10 to 20 percent.
South Carolina will be mostly cloudy in the west, and partly cloudy in the central and eastern parts of the state. There is a chance of showers and thunderstorms in the west and along the coast. High temperatures will be 75 to 85. Winds will be northwest to north at 10 to 15 mph. Minimum relative humidities will range from 35 to 50 percent.
Southern California will be sunny except for patchy morning fog along the coast. Temperatures will be from the mid 70’s in coastal areas up to 115 in the deserts. Winds will be upslope or up valley at 5 to 15 mph in the afternoon. Minimum relative humidity inland will be 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
Fig. 4. 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.
