Wildfires - April 2009

Updated: 7 May 2009

April saw several significant wildfires that scorched thousands of acres apiece, displaced hundreds of people and destroyed a number of homes.  The month began in earnest with six large fires burning in Texas, five in Florida, and one each in Arizona and New Mexico.  High winds and low humidity fanned conflagrations in northern Texas and western and central Oklahoma in the early part of April, prompting the evacuation of several towns.  In the last week of April, clusters of large fires existed in western Texas, northeastern Oklahoma, and eastern Kentucky.  In addition, a large wildfire, believed by forestry officials to have been started by the uncontrolled burning of yard waste, burned nearly 20,000 acres (8,093 hectares) and destroyed or damaged at least 150 homes around the oceanfront resort community of North Myrtle Beach, South Carolina.

Links to Large Fire Maps:
[ April 1 |  April 14 |  April 27 ]

According to statistics from the National Interagency Fire Center (NIFC), between April 3rd and May 1st approximately 485,373 acres (196,424 hectares) were burned across the United States.  A total of 10,009 new wildfires were reported, which is 2,090 above the 2000–2009 average of 7,919 fires.  This is the second greatest number of fires in April, behind 2006.  The total acreage burned during April 2009 was 207,731 acres (84,066 hectares) above the 2000–2009 average of 277,642 acres (112,358 hectares), and for that 10–year period was the second greatest acreage burned in April after 2008.  Average fire size in April 2009 was 48.5 acres (19.6 hectares) burned per fire.  This value is 13.6 acres (5.5 hectares) per fire above the 2000–2009 average fire size of 34.9 acres (14.1 hectares) per fire.  For the period 2000–2009, the number of acres burned in April has increased by just under 48,000 acres per year, and for the period 2005–2009, that rate has increased to nearly 118,000 acres per year.

For the period from January 1st through May 1st, total year–to–date acreage burned was 1,064,711 acres (430,873 hectares), which was 295,746 acres (119,685 hectares) above the 2000–2009 average of 768,965 acres (311,190 hectares), and the third greatest amount of acreage burned for the period since 1999.  The year–to–date (January – April) number of fires was 32,063, or 7,514 fires above the 2000–2009 average of 24,550 fires.  This ranks 2009 as second for year–to–date number of fires, behind 2006.  Combined, the year to date number of fires and acreage burned yields an average of 33.2 acres (13.4 hectares) per fire.

The cumulative number of fires and acres burned to date in 2009 have consistently exceeded their respective 10–year averages, and the difference appears to be increasing in magnitude.  A comparison between early season fire totals and acreage burnt reveals that early season fire activity shows a strong and significant correlation with end–of–year totals.  While the small number of years limits confidence in any estimates, this strong relationship coupled with the above average fire behavior thus far for 2009, indicates that this year is increasingly likely to see an above average fire season.

Cumulative statistics for 2009:
[ Number of Fires  |  Acres Burned ]

According to the U.S. Drought Monitor, for the second month in a row drought conditions continued to improve in the western Carolinas and along the Appalachian mountains.  An improvement in drought conditions was also seen in parts of Hawai'i during April, but at the same time, drought worsened across southern Florida.  A large area of severe to exceptional drought persisted through April across southern and central Texas, and extreme drought developed in southern Florida by the end of the month.

According to the U.S. Forest Service (USFS) – Wildland Fire Assessment System, relatively low fire danger was present across much of the U.S at the beginning of the month, with high to very high danger limited to areas of the southwestern U.S., from central California eastward to Great Plains, and in the eastern U.S. from western Indiana to the Atlantic coast.  By the end of April, high to extreme fire danger had consolidated around central New Mexico, extending northward into Colorado, east into Texas and west to Nevada and southern California.  High to very high fire danger also developed across the northeastern states of Maine, Vermont, New Hampshire, Massachusetts and eastern New York by the end of the month.

Links to Fire Danger Maps:
[ March 31  |  April 30 ]

2009 Wildfire Statistics

(Source: NIFC)
Year–To–Date Totals as of May 1st Nationwide Number of Fires Nationwide Number of Acres Burned
05/01/2009 32,063 1,064,711
05/01/2008 20,067 1,323,614
05/01/2007 25,074 493,590
05/01/2006 35,102 2,251,409
05/01/2005 18,371 267,689
05/01/2004 24,573 375,934
05/01/2003 15,513 328,930
05/01/2002 23,776 382,634
05/01/2001 22,941 468,563
05/01/2000 28,015 732,579
5–yr average
(2005 – 2009)
26,135 1,080,203
10–yr average
(2000 – 2009)
24,550 768,965

April began with critically low 10–hour dead fuel moisture levels encompassing an area from western Texas into Oklahoma, and across to Nevada and central California.  In the eastern U.S., low moisture levels were present from Ohio to the Atlantic coast and south to South Carolina.  At the end of the month, critically dry 10–hour fuel levels covered much of the southwestern U.S., from extreme western Texas northwest to northwestern Colorado and across to Nevada and central California.  Ten–hour fuel moisture also dried significantly across much of the northeastern states, reaching critical levels in parts of Maine, New Hampshire and Vermont at the end of April.  Decreases in 10–hour fuel moisture levels also occurred across much of the southeastern U.S. during the month.

The 100–hour and 1000–hour fuel moisture levels were generally low across much of the west–central United States at the beginning of April, with critically dry 100–hr moisture levels along the southwestern U.S. border in Arizona, New Mexico and western Texas.  Florida also experienced moderately dry 100–hour moisture levels at the start of the month.  By April's close, critically low 100–hour moisture levels had expanded northward into southern Colorado and central Nevada.  Large fuel moisture had also dried out across much of the eastern U.S. toward the end of the month.

Links to 10–hour Fuel Moisture Maps:
[ March 31  |  April 30 ]

Links to 100–hr Fuel Moisture Maps:
[ March 31 |  April 30 ]

Links to 1000–hr Fuel Moisture Maps:
[ March 31  |  April 30 ]

The Keetch–Byram Drought Index (KBDI), a widely used drought index for fire risk, showed critically dry conditions in southern Texas, central Nevada, and southern Florida at the beginning of April.  The KDBI showed little spatial change throughout the month for most of the nation.  However, the KBDI increased to moderate levels along the Gulf Coast and southern Mid–Atlantic regions, and to severe levels across much of southern Florida and southern Texas during April.

Links to KBDI Maps:
[ March 31  |  April 30 ]

Citing This Report

NOAA National Centers for Environmental Information, State of the Climate: Wildfires for April 2009, published online May 2009, retrieved on January 24, 2018 from https://www.ncdc.noaa.gov/sotc/fire/200904.