Wildfires - September 2008
The number of active large wildfires decreased during the month of September. However, three firefighters lost their lives in the effort when their P2V Air Tanker crashed on takeoff from Reno–Stead Airport in Nevada on September 1st. The month opened with large fires being fought in eight states. However, by mid–month, just three states (California, Oregon and Idaho) were battling large wildfires. At the end of September, large wildfires were burning in California, Arizona and Oregon.
Large Fire Maps:
According to statistics from the National Interagency Fire Center (NIFC), between August 29th and September 29th approximately 155,040 acres (62,743 ha) were burned across the United States and approximately 3,534 new wildfires were reported. This latter value represents the fewest fires in September in the past 10 years, and approximately 2,820 fewer fires than the 1999–2008 average. Overall acreage burnt in September was the second lowest for the month in the past decade, and was nearly a half million acres (202,000 ha) below the 1999–2008 average, as well as over 1.3 million acres (526,000 ha) fewer than that burnt in September 2006, the worst year in the past decade.
As of September 29th, 67,568 wildland fires have burned approximately 4.7 million acres (1.9 million ha) in 2008, according to NIFC. Although the season began ominously, this year–to–date period now ranks fourth lowest since 1999 with respect to quantity of acreage burnt. For the period from January 1st to September 29th, total acreage burnt falls nearly 1.5 million acres below the 1999–2008 average of 6,218,429 acres (2,516,519 ha), while the 67,568 fires between January 1st and September 29th is near the 10–year average of 67,518 fires, indicating that many of this year's fires were contained to small areas. Six hundred ninety–seven large fires have been contained this year through September 29th.
The U.S. Drought Monitor indicated that drought conditions deteriorated slightly across much of the western and southeastern U.S. through September (see the U.S. Drought Monitor Change Map for more information). At the end of September, much of the western U.S. remained in moderate to severe drought. Severe to extreme drought continued across portions of eastern Montana and western North Dakota, and extreme to exceptional drought persisted in the western Carolinas despite much–needed rainfall from a sub–tropical cyclone that moved across the region in late September. The persistent drought conditions have kept fire danger levels high in many areas of the western United States, although some reductions in fire danger are evident at the end of September.
High to extreme fire danger that had been centered on central California and Nevada spread into the Pacific Northwest, and eastward to a line from Montana to Arizona in the first half of September. Conditions improved in many areas of the western U.S. during the second half of the month, but isolated pockets of high to very high fire danger developed in South Dakota, along the Kansas – Missouri border, and in several locations in the southeastern United States, according to the U.S. Forest Service (USFS) – Wildland Fire Assessment System.
Fire Danger Maps:
2008 Wildfire Statistics(Source: NIFC)
|Year–To–Date Totals as of September 29th||Nationwide Number of Fires||Nationwide Number of Acres Burned|
(2003 – 2007)
(1999 – 2008)
The area of critically low 10–hour dead fuel moisture levels, which had covered an area from central California northeastward to the central Dakotas at the beginning of the month, expanded into the western High Plains and south into Texas by the end of September. Decreases in 10–hour dead fuel moisture were also occurring in portions of the Great Plains and the Southeast.
Critically low medium to large fuel moisture levels (i.e., see September 30th 100–hr and 1000–hr fuel moistures) followed a similar pattern to the 10–hour fuel moisture, with dry conditions in the western U.S., centered on Nevada.
10–hr Fuel Moisture Maps:
The Keetch–Byram Drought Index (KBDI), a widely used drought index for fire risk, showed extremely dry conditions throughout most of the western U.S. west of the Rocky Mountains. California, Nevada and western Oregon were particularly dry. Smaller regions of high fire risk occurred in western North Dakota and across parts of east–central Texas. Fire risk diminished along the mid–Atlantic coast during the month, but a substantial area of high fire risk developed across Kentucky and eastern Tennessee in conjunction with abnormally dry conditions from central Indiana to the Gulf Coast.