March 2009 Wildfires Report

Large fires – 31 March 2009

Updated: 10 April 2009

March began with 35 wildfires, most of which were clustered in central Texas and eastern Oklahoma, with additional fires in Florida, Kansas, Missouri, Tennessee, and North Carolina.  By mid–month, wildfire activity had been largely contained, with just 7 active large fires by March 20^th, however dry and windy conditions in Florida facilitated a number of wildfires throughout the month.  The closing of March saw a slight increase to 13 fires, mostly in parts of Texas and Florida.

Links to Large Fire Maps:
[ February 27 |  March 13 |  March 18 |  March 31 ]

Number of Fires and Acres Burned in March (1999–2009)

According to statistics from the National Interagency Fire Center (NIFC), between February 27^th and April 3^rd approximately 401,741 acres (162,579 hectares) were burned across the United States.  A total of 14,078 new wildfires were reported, which is 3,341 above the 2000–2009 average of 10,737 fires.  This is the third greatest number of fires in March behind 2006 and 2004, but is 2,291 fewer fires than the highest value in 2006.  The total acreage burned during March 2009 was 55,388 acres (22,415 hectares) above the 2000–2009 average of 346,353 acres (140,165 hectares), and for that 10–year period was the second greatest acreage burned in March after 2006.  Average fire size in March 2009 was 28.54 acres (11.55 hectares) burned per fire.  This value is just slightly below the 2000–2009 average fire size.

Acres Burned per Fire in March (1999–2009)

For the period from January 1^st through April 3^rd, total year–to–date acreage burned was 579,338 acres (234,451 hectares), which was 88,015 acres (35,619 hectares) above the 2000–2009 average of 491,324 acres (198,832 hectares), and third greatest amount of acreage burned for this period since 1999.  The year–to–date (January – March) number of fires was 22,054, or 5,424 fires above the 2000–2009 average of 16,630 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 26.27 acres (10.63 hectares) per fire.

Of particular note is that the cumulative number of fires and acres burned to date in 2009 have consistently exceeded their respective 10–year averages.  Although the period January–March is not traditionally considered part of the U.S. wildfire season, the high number of pre–season fires is significant because over the past decade, the number of fires by April 3^rd correlates very strongly with the total number of fires at the end of the year.  For the 2000–2008 period, the correlation between April 3^rd and end–of–year number of fires is 0.66 (1.0 being a perfect relationship).  If 2004 is not considered, that correlation strengthens to 0.94.  While the small number of years limits confidence in any estimates, this strong relationship indicates that 2009 is likely to see an above average fire season.

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

U.S. Drought Monitor map from 24 March 2009

According to the U.S. Drought Monitor, drought conditions improved slightly in the western Carolinas and northern California, but deteriorated across Florida in March.  A large area of severe to exceptional drought persisted through March across southern and central Texas, as did an area of severe to extreme drought in parts of Hawai'i.

Fire Danger map from 31 March 2009

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 areas of high to very high danger limited to the Gulf Coast from the Mexico/Texas border to Alabama, and to the southwestern border regions of the U.S., extending northward into southeastern Wyoming.  By the end of March, fire danger had decreased across most of the U.S. Gulf Coast, but remained high to extreme in many parts of the Southwest.  Areas of high to very high fire danger had also appeared in parts of the Midwest, Central Plains, Ohio Valley, and the Mid–Atlantic by the end of the month.

Links to Fire Danger Maps:
[ March 1  |  March 17  |  March 31 ]

March began with critically low 10–hour dead fuel moisture levels encompassing an area from Texas, up to Kansas, and across to southern California.  By mid–month, conditions had improved somewhat in isolated parts of the Southwest, but dried out across Nevada and eastward across the Midwest into the Ohio Valley.  Much of the Southeast also experienced a decrease in dead fuel moisture.  At the end of the month, critically dry 10–hour fuel levels covered most of the southwestern U.S., from Texas north to Kansas and across to California.  Additional drying occurred in Florida and throughout the eastern U.S. from eastern Georgia north to Pennsylvania and westward into Ohio.

The 100–hour and 1000–hour fuel moisture levels were generally low across much of the west–central United States at the beginning of March, with critically dry 100–hr moisture levels concentrated along the southwestern U.S. border in Arizona, New Mexico and western Texas.  Florida and an area centered on New York City also experienced moderately dry 100–hour moisture levels at the start of the month.  By mid–March, 100–hour moisture levels along the southwestern border regions had recovered slightly, but dry conditions continued across much of the western U.S., and expanded into the Midwest as well as Maine.  Conditions across the eastern Midwest and Maine improved by the end of March, but critically low 100–hour moisture levels returned to the southwest border regions.

Links to 10–hour Fuel Moisture Maps:
[ March 1  |  March 17  |  March 31 ]

Links to 100–hr Fuel Moisture Maps:
[ March 1 |  March 17 |  March 31 ]

Links to 1000–hr Fuel Moisture Maps:
[ March 1  |  March 17  |  March 31 ]

Keetch–Byram Drought Index map from 31 March 2009

The Keetch–Byram Drought Index (KBDI), a widely used drought index for fire risk, showed critically dry conditions in southern Texas and southern Florida at the beginning of March.  The KDBI showed little change throughout the month for most of the nation, save for the expansion of dry conditions in Texas and Florida, and deterioration across Nevada.

Links to KBDI Maps:
[ March 1  |  March 17  |  March 31 ]

Additional Links

• NOAA Fire Products
• U.S. Drought Monitor
• National Interagency Fire Center
• U.S. Forest Service Active Fire Mapping Program
• Wildland Fire Assessment System
• Alaska Interagency Coordination Center
• Canadian Interagency Forest Fire Center

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