Wildfires - August 2009


Updated: 10 September 2009

Despite a substantial fire outbreak in California toward the end of August, and up to 36 large fires burning at once, August closed near average in terms of both the number of wildfires and the acreage burned throughout the nation.  With the exception of one large fire during the first half of the month in coastal North Carolina, all large fires in August were concentrated in the western half of the United States, including Alaska.  According to information from the National Interagency Fire Center, August started off with 21 large fires in 12 states, including three each in Alaska, Oregon, Washington, and Utah.  At mid–month, 20 large fires were active in eight states, especially in California where seven large fires were burning, and in Alaska with four fires.  At the end of August, 21 large fires were burning in seven states — 12 of these occurring in California.  Unfortunately, on August 31st, two firefighters were killed while fighting the fires in the Angeles National Forest near Los Angeles, CA.  According to news reports, the fire, which was only 5 percent contained on the 31st had already destroyed 21 homes and trapped 5 people who had refused to evacuate.  By September 1st, the fire had doubled in size and was threatening several thousand homes in more densely populated areas of the region.

2009 Wildfire Statistics

(Source: NIFC)
Year–To–Date Totals as of August 31st Nationwide Number of Fires Nationwide Number of Acres Burned
08/31/2009 64,682 5,238,183
08/31/2008 63,945 4,549,283
08/31/2007 64,796 6,890,431
08/31/2006 78,633 7,575,768
08/31/2005 45,165 7,316,440
08/31/2004 54,483 6,716,487
08/31/2003 43,776 2,574,831
08/31/2002 60,672 6,204,511
08/31/2001 56,936 2,823,807
08/31/2000 71,510 6,002,534
5–yr average
(2005 – 2009)
63,444 6,314,021
10–yr average
(2000 – 2009)
60,460 5,589,228

According to statistics from the National Interagency Fire Center (NIFC), between August 1st and August 31st approximately 1,646,363 acres (666,259 hectares) were burned across the United States.  The total acreage burned during August 2009 was just 64,814 acres (26,229 hectares) below the 2000–2009 average of 1,711,177 acres (692,489 hectares), and for that 10–year period was the sixth lowest August for acreage burned.  A total of 7,975 new wildfires were reported, which is 231 fewer than the 2000–2009 average of 8,206 fires.  This is the fifth fewest fires in August in the past decade.  Average fire size in August 2009 was 206.4 acres (83.5 hectares) burned per fire.  This value is just 5.8 acres (2.3 hectares) per fire below the 2000–2009 average fire size of 212.2 acres (85.9 hectares) per fire.

For the period January 1st through August 31st, total year–to–date acreage burned was 5,238,183 acres (2,119,817 hectares), which was 351,045 acres (142,063 hectares) below the 2000–2009 average of 5,589,228 acres (2,261,880 hectares), and the seventh greatest amount of acreage burned for the period since 1999.  The year–to–date (January – August) number of fires was 64,682, or 4,222 fires above the 2000–2009 average of 60,460 fires.  This ranks 2009 as the fourth highest year–to–date for number of fires over the past decade for the second consecutive month.  Combined, the year–to–date number of fires and acreage burned yields an average of 81.0 acres (32.8 hectares) per fire relative to the 2000–2009 average of 93.5 acres (37.8 hectares) per fire.

According to the U.S. Drought Monitor, extreme to exceptional drought conditions persisted across much of southern Texas in August, exacerbating potential fire danger in that region.  Drought conditions worsened in Arizona throughout the month, but improved in northern Wisconsin.  Drought conditions across much of California have remained relatively unchanged since the start of June.

According to the U.S. Forest Service (USFS) – Wildland Fire Assessment System, very high to extreme fire danger continued to impact the western United States in August.  However, fire danger in the Pacific Northwest and the North Central United States decreased appreciably between the start and middle of the month, with areas of very high to extreme danger concentrated primarily in California, Arizona, Nevada and Utah.  By the end of August, high fire danger had returned to southeastern Montana and isolated parts of the Pacific Northwest.  It also spread eastward from Utah to include western Colorado.  In general, Alaska and eastern parts of the contiguous United States were in low to moderate fire danger throughout August.

Extremely low 10–hour dead fuel moisture levels persisted across much of the western United States during August. In Alaska, the low 10–hr dead fuel moisture that began the month across the eastern half of the state recovered by the end of August to more moderate levels.

In a pattern similar to the 10–hr dead fuel moisture levels, low 100–hour and 1000–hour fuel moisture levels persisted across much of the western United States throughout August, with little change through the month.  In general the eastern half of the contiguous United States saw moderate to high fuel moisture levels in August.  The moderate moisture levels of larger fuels in Alaska at the start of August had also recovered by the end of the month.

The Keetch–Byram Drought Index (KBDI), a widely used drought index for fire risk, remained relatively unchanged across the contiguous United States during August.  Dangerously dry conditions continued to be indicated in southern Texas and across a region westward of a line from southern Arizona northwest to northwestern Washington.  The KBDI indicated very low risk across Alaska throughout August.


Citing This Report

NOAA National Climatic Data Center, State of the Climate: Wildfires for August 2009, published online September 2009, retrieved on October 31, 2014 from http://www.ncdc.noaa.gov/sotc/fire/2009/8.