Wildfires - December 2009

Issued: 8 January 2010

December is typically a quiet month for wildfires, and December 2009 was no exception. There were 831 fires that burned 30,668 acres over the course of the month, compared to the decadal average of 2,927 fires burning 98,703 acres. This ranked December 2009 as the 2nd lowest number of fires and 4th lowest acreage burned since 2000. The low fire numbers for the month of December were associated with abnormally cool and wet conditions for the month – see the monthly temperature and precipitation discussion.

Throughout December, only six large fire incidents were reported across the country. There was one large fire in eastern Oklahoma, one in eastern Tennessee, and one central Florida the first week of December. There were two large fire reports in Oklahoma the second week of the month and one report in Oklahoma the third week. The last week of the month did not have any large fire activity.

2009 Wildfire Statistics

(Source: NIFC)
Year–To–Date Totals as of December 31st Nationwide Number of Fires Nationwide Number of Acres Burned
12/31/2009 77,315 5,914,821
12/31/2008 77,772 5,159,907
12/31/2007 85,705 9,328,045
12/31/2006 96,385 9,873,745
12/31/2005 66,753 8,689,389
12/31/2004 65,461 8,097,880
12/31/2003 63,629 3,960,842
12/31/2002 73,457 7,184,712
12/31/2001 84,079 3,570,911
12/31/2000 92,250 7,393,492
5–yr average
(2005 – 2009)
80,786 7,793,181
10–yr average
(2000 – 2009)
78,281 6,917,375

Statistics from the National Interagency Fire Center (NIFC) show that between November 28th and December 31st, approximately 30,668 acres (12,411 hectares) burned across the United States. The total acreage burned during December 2009 was 68,035 acres (27,533 hectares) below the 2000–2009 average of 98,703 acres (39,944 hectares), and for the 10–year period was the 4th lowest December for acreage burned. A total of 831 new wildfires were reported, which is 2,096 fewer than the 2000–2009 average of 2,927 fires. This marks the 2nd fewest number of fires in December during the past decade, above the 544 fires during December 2008. The average fire size in December 2009 was 37 acres (14.93 hectares). This is 1.57 acres (0.64 hectares) larger than the 2000-2009 average fire size of 35.33 acres (14.3 hectares).

For the period January 1st through December 31st, total acreage burned was 5,914,821 acres (2,393,643 hectares), which was 1,113,948 acres (450,799 hectares) below the 2000–2009 average of 7,028,769 acres (2,844,442 hectares), and the fifth lowest amount of acreage burned for the period since 2000. The annual number of fires was 77,315, or 1,073 fires below the 2000–2009 average of 78,388 fires. This ranks 2009 as the fifth lowest year for number of fires over the past decade. Combined, the annual number of fires and acreage burned yields an average of 77 acres (30.96 hectares) per fire, relative to the 2000–2009 average of 90.46 acres (36.61 hectares) per fire.

The U.S. Drought Monitor indicated that drought conditions improved across the eastern half of the country as well as in southern Texas over the course of the month. Areas of moderate to severe drought continued for Hawaii and Arizona, marking little change since November. Abnormally dry conditions expanded across central Alaska.

According to the U.S. Forest Service (USFS) – Wildland Fire Assessment System, the majority of the nation was under low to moderate fire danger throughout the month. The exceptions were a few small pockets of high danger in California, Nevada, Arizona, and Georgia.

At the beginning of the month, low 10–hour fuel moistures were present from Colorado, across the four corners region and into California. There were relatively low 10–hour fuel moisture in Nebraska, Kansas, Iowa, and Missouri. The Mid-Atlantic States were also experiencing low fuel moistures. By the end of December, the abnormally cool and wet conditions across the country almost eliminated all low 10–hour fuel moistures except for the extreme Southwest, western Texas, and southern Florida.

At the start of December, low 100–hour and 1000–hour fuel moistures were prevalent west of the Mississippi except in the Pacific Northwest. By then end of the month, abnormally dry larger fuels were contained to the extreme Southwest.

The Keetch–Byram Drought Index (KBDI), a widely used drought index for fire risk, at the beginning of the month indicated continued dryness and thus fire risk across much of California and Florida, but not as extreme as during November. High KBDI values were also found in eastern Nevada, western Texas, Arizona, and eastern Washington during the middle of the month. By the end of the month the extent of the fire risk had shrunk considerably. The highest KBDI values were contained to Nevada, parts of southern California and eastern Arizona.

Citing This Report

NOAA National Climatic Data Center, State of the Climate: Wildfires for December 2009, published online January 2010, retrieved on January 30, 2015 from http://www.ncdc.noaa.gov/sotc/fire/2009/12.