Wildfires - October 2009


Issued: 6 November 2009

Keeping in line with the close of the traditional wildfire season in the United States, October 2009 saw relatively light fire activity. As with September, fire activity in October was below average in all respects.  For the month, 3,207 fires burned 158,644 acres across the nation.

October began with 13 large wildfires burning in six states (four in Montana, three each in Oregon and Wyoming, and one apiece in Arizona, California, and Idaho.  However, by mid–month, just three large wildfires remained active – one each in Washington, Oregon and northern California.  There were no large wildfires burning between October 17th and the 20th.  Only three large fires occurred between October 21st and the end of the month – two in Arizona and one in California.  At the end of the month, one large fire in Arizona was still active.

2009 Wildfire Statistics

(Source: NIFC)
Year–To–Date Totals as of October 29th Nationwide Number of Fires Nationwide Number of Acres Burned
10/29/2009 73,424 5,775,350
10/29/2008 73,862 5,040,873
10/29/2007 77,062 9,189,460
10/29/2006 86,545 9,442,610
10/29/2005 56,812 8,261,021
10/29/2004 69,011 8,179,098
10/29/2003 55,914 3,500,711
10/29/2002 69,372 6,707,669
10/29/2001 67,417 3,128,303
10/29/2000 87,809 7,048,206
5–yr average
(2005 – 2009)
73,541 7,541,863
10–yr average
(2000 – 2009)
71,723 6,627,330

Statistics from the National Interagency Fire Center (NIFC) show that between October 1st and October 29th approximately 158,644 acres (64,201 hectares) were burned across the United States.  The total acreage burned during October 2009 was 173,199 acres (56,662 hectares) below the 2000–2009 average of 331,843 acres (120,863 hectares), and for that 10–year period was the fourth lowest October for acreage burned.  A total of 3,207 new wildfires were reported, which is 1,652 fewer than the 2000–2009 average of 4,859 fires.  This is the third fewest fires in October in the past decade.  Average fire size in October 2009 was 49.5 acres (20.0 hectares) burned per fire.  This value is 26.6 acres (7.7 hectares) per fire below the 2000–2009 average fire size of 76.0 acres (27.7 hectares) per fire.

For the period January 1st through October 29th, total year–to–date acreage burned was 5,775,350 acres (2,337,201 hectares), which was 851,980 acres (344,784 hectares) below the 2000–2009 average of 6,627,330 acres (2,681,985 hectares), and the fourth lowest amount of acreage burned for the period since 1999.  The year–to–date (January – October) number of fires was 73,424, or 1,701 fires above the 2000–2009 average of 71,723 fires.  This ranks 2009 as the fifth highest year–to–date for number of fires over the past decade.  Combined, the year–to–date number of fires and acreage burned yields an average of 78.7 acres (31.8 hectares) per fire, relative to the 2000–2009 average of 92.5 acres (37.4 hectares) per fire.

The U.S. Drought Monitor indicated that drought conditions improved in parts of Wisconsin and southeastern Texas during October.  Slight improvements also were noted in parts of the West, including areas of central California, western Montana and coastal regions of Oregon and Washington.  Moderate to severe drought remained over much of the far West and Hawai'i, as well as southern Texas.  Parts of Hawai'i, southern Texas, and northern Wisconsin were under extreme to exceptional drought conditions at the end of October.

According to the U.S. Forest Service (USFS) – Wildland Fire Assessment System, high to extreme fire danger was impacting parts of the western and much the southwestern United States at the start of October.  However, by the middle of the month, fire danger was low to moderate across nearly all of the contiguous U.S.  Cold temperatures and early snows helped to reduce fire danger to low or negligible levels across all but extreme southwestern parts of the United States by the end of October.

Following the pattern of fuel moisture levels experienced throughout much of 2009, October's 10–hour fuel moisture levels were lowest in the Southwest U.S., with parts of Nevada, Arizona, and southern California at critically low moisture levels at the start of the month.  Significant improvements in fuel moisture were evident by the middle of the month over most of the nation, but parts of the Southwest returned to critically dry 10–hr levels by the end of October.

Patterns of 100–hour and 1000–hour fuel moisture were similar to those of 10–hr fuel moisture in October — both across the coterminous U.S. and in Alaska.  In the lower 48 states, relatively dry larger fuel moisture levels were present west of the Great Plains at the start of October, but by the end of the month, larger fuel moisture levels increased across the nation, save portions of the Southwest.

The Keetch–Byram Drought Index (KBDI), a widely used drought index for fire risk, showed improvement across much of the United States during October, especially in the West.  Dangerously dry conditions were present throughout much of the western U.S. at the start of the month, but conditions improved as October progressed.  At the end of the month, only small pockets of high KBDI were present in the West.


Citing This Report

NOAA National Climatic Data Center, State of the Climate: Wildfires for October 2009, published online November 2009, retrieved on September 30, 2014 from http://www.ncdc.noaa.gov/sotc/fire/2009/10.