Wildfires - October 2008

October began with several large wildfires active in California (4), Oregon (4), Idaho (1), and Colorado (1). By the middle of the month, however, just five large fires were active, all in California. At the end of October, one fire remained active in California, while three others kindled in Utah, Arizona, and Oklahoma. Santa Ana winds during the middle of the month hampered efforts to battle several large wildfires in Southern California (see NASA's Aqua Satellite mission image page for higher resolution images).

According to statistics from the National Interagency Fire Center (NIFC), between September 30th and October 31st approximately 323,495 acres (130,914 ha) were burned across the United States and approximately 6,392 new wildfires were reported. This latter value represents the third most fires in October in the past 10 years, and approximately 1,728 more fires than the 1999–2008 average. Overall acreage burnt in October however, was near average for the month – only 13,715 acres (5,550 ha) below the 1999–2008 average.

For the year–to–date through October 31st, 73,960 wildland fires have burned approximately five million acres (2 million ha), based upon data from NIFC. Although the season began ominously, this year–to–date period now ranks third lowest since 1999 with respect to quantity of acreage burnt. For the period from January 1st to October 31st, total acreage burnt was just over 1.5 million acres below the 1999–2008 average of 6,555,639 acres (2,652,984 ha). However, the number of fires between January 1st and October 31st was well above the 10–year average of 72,182 fires, indicating that there was a relatively high contribution from small area fires this year. Seven hundred two large fires have been contained this year through October 31st.

The U.S. Drought Monitor indicated that drought conditions remained relatively unchanged across much of the western and southeastern U.S. during October (see the U.S. Drought Monitor Change Map for more information). At the end of October, much of the western U.S. remained in moderate to severe drought. Severe to extreme drought was present in southern Texas, the southern and central Appalachians, and across the Hawaiian Islands as November approached. Extreme to exceptional drought persisted in the western Carolinas. The persistent drought conditions have kept fire danger levels high in many areas of the western United States throughout this 2008 fire season, although widespread elevated fire danger has recovered in many parts of the West during October.

As a result of the relative dryness across many parts of the nation, fire danger was moderate across the majority of the contiguous United States at the end of October. The month began with high to very high fire danger across the majority of western States. However, mid–month precipitation improved conditions in the northwestern U.S., leaving only southern California, Arizona, and southern Nevada in very high to extreme fire danger. Fire danger conditions in the Southwest improved near the end of October, but worsened in northern Nevada as well as an area including parts of Wyoming, South Dakota, Nebraska, eastern Montana, and northern Colorado, according to the U.S. Forest Service (USFS) – Wildland Fire Assessment System.

2008 Wildfire Statistics

(Source: NIFC)
Year–To–Date Totals as of October 31st Nationwide Number of Fires Nationwide Number of Acres Burned
10/31/2008 73,960 5,052,109
10/31/2007 77,108 9,191,148
10/31/2006 86,976 9,445,153
10/31/2005 56,850 8,261,437
10/31/2004 63,047 8,044,834
10/31/2003 56,036 3,511,752
10/31/2002 69,413 6,684,556
10/30/2001 67,604 3,779,562
10/31/2000 87,809 7,048,206
5–yr average
(2003 – 2007)
68,003 7,690,865
10–yr average
(1999 – 2008)
72,182 6,555,639

The large area of critically low 10–hour dead fuel moisture levels, extending from the Dakotas, Nebraska, Kansas, Oklahoma, and Texas, all the way to the western coast, shrank considerably by mid–October. However, most of California, Nevada, and Arizona remained at severely low 10–hour dead fuel moisture levels. By the end of the month critical conditions shifted eastward into New Mexico, Arizona, Colorado, Wyoming, Nebraska, and small portions of Oklahoma, Texas, South Dakota, and Utah. The eastern U.S. also showed a deterioration of 10–hour moisture levels, especially in the southern Appalachian region, the mid–Atlantic and central Louisiana. Minnesota, which had maintained relatively high levels of 10–hour fuel moisture into the start of October, dried out significantly by October 31st.

Medium to large fuel moisture levels, which had been critically low across much of the western U.S. improved during the first half of October, especially in the northern and central regions of the nation. However, 100–hour moisture levels also dried across the central Appalachians and New England by mid–month. Unfortunately, the improvements seen early in the month in western and central areas of the country returned to critically dry conditions toward the end of the month. Moisture levels in the 1000–hour fuels followed a pattern similar to the 100–hour fuels in October.

1000–hr Fuel Moisture Maps:

The Keetch–Byram Drought Index (KBDI), a widely used drought index for fire risk, showed extremely dry conditions at the beginning of the month throughout the western U.S., including California, Nevada, and western Oregon. In the eastern U.S., Kentucky and parts of eastern Tennessee displayed high levels of risk. Smaller exceptionally dry patches also occurred in eastern central Texas, central New Mexico, and western North Dakota. Fire risk diminished towards the middle of the month in both the western and eastern U.S., though areas of California, Nevada, eastern central Texas, and Kentucky remained exceedingly dry. The end of the month showed fewer areas of high fire risk, with the exceptions of extreme dry conditions persisting in California and Nevada, and small sections of Texas and Kentucky.

Citing This Report

NOAA National Climatic Data Center, State of the Climate: Wildfires for October 2008, published online November 2008, retrieved on April 18, 2014 from http://www.ncdc.noaa.gov/sotc/fire/2008/10.