This year, 2010, is shaping up to be the the quietest wildfire season in the United States since 1998, when measured by acres burned. If you separate Alaska from the rest of the country, through November 4, 2010 the lower 49 states have burned the fewest acres since 2004. Alaska can routinely have mega-fires, or a very quiet fire season, so adding their numbers in with the rest of the country can really skew the trend. For example, in 2004, four times as many acres were blackened in Alaska than in the other 49 states combined.
The following numbers were obtained from the http://www.nifc.gov/ site, which has had problems recently and is not always available. The 2010 stats here go through November 4, 2010.
The stats for the number of acres burned in all 50 states from 1960 through 2010 are below.
Here is an excerpt from an article in USA Today, quoting Rick Ochoa, fire weather program manager of the fire center in Boise:
Ochoa says persistently cool, wet weather in the normally arid and fire-plagued West throughout the late spring and summer were the primary factors for the drop in acres burned. “The West never really dried out or warmed up,” Ochoa adds.
The South was also wetter than average. “We had an El Niño earlier this year, which typically produces a wet pattern over the southern tier of states,” he says.
The El Niño and the La Niña climate patterns — warming and cooling of tropical Pacific Ocean waters — strongly affect weather conditions in the USA. During a La Niña pattern, conditions are dry across southern states.
More than a third of wildfires this year were human-caused, either accidentally or deliberately.
Ochoa says 63% of the acres burned were because of lightning and 37% were human-caused. “In general, about 75% of the western fires are historically caused by lightning,” he says.
The transition from an El Niño to a La Niña this past summer, along with ongoing drought, will increase the likelihood for wildfires across the southern USA through the winter and into the spring, Ochoa says.
“Because we have that strong La Niña, it should be dry from eastern New Mexico to Texas to Florida,” he notes. Wildfires are most common through the winter in the southern Plains, and in March in Florida.
The dryness is already causing problems in Texas and Oklahoma, according to the most recent U.S. Drought Monitor, a weekly government publication. It said: “Some impacts on crops, grasslands, and livestock upkeep have been reported, and burn bans have been mandated in a number of counties in this region.”