Predicting the severity of fire seasons

I stopped trying to predict the severity of fire seasons long ago. The most important factor is the weather during the season. If it is hot, dry, and windy, you can have a busy season. If it is not, even with a heavy fuel buildup and/or drought, you are not likely to have numerous large fires.

An article in the March/April issue of Wildfire by Krista Gebert, an economist with the US Forest Service, showed a relationship between the average spring-summer temperature and total fire suppression expenditures in the US Forest Service's Northern Region (Montana, and parts of Idaho, North Dakota, and Washington). The threshold was 59-degrees (15 degrees C). When the average was below 59, the total fire suppression expenditures were generally less than $50 million per year. When the average was above 59, expenditures ranged from as low as $25 million to as high as $350 million.

Isn't it great when a researcher, or even an economist, crunches numbers at a desk and tells us what experienced fire managers already know. But you don't see experienced fire managers writing up stuff like this. The fact that Ms. Gebert is documenting it, and backing it up with data, reduces the learning curve for people coming into the wildland fire game. And this data may improve some of the predictive services tools and products.

In the article below, from the San Diego Union about the fuel buildup in Arizona, a fire meteorologist takes a bold step and predicts a "substantial fire season" for the greater Phoenix area.

By Amanda Lee Myers

ASSOCIATED PRESS

12:45 p.m. April 3, 2008

PHOENIX – An abnormally wet winter has spawned a rare profusion of grass and brush in the Phoenix metro area and other parts of the state – setting up much of Arizona's desert lands for an active wildfire season, according to fire management officials.

That same wet weather has been a blessing for the state's higher-elevation forests, which have been dried out by years of drought and left with millions of dead trees because of a beetle infestation.

For the forests, above-normal snowfalls mean trees and undergrowth will have high moisture content, and the fire danger is expected to be relatively low.

But by May, searing temperatures and arid conditions are expected to dry out the often hip-high grasses now blanketing desert areas.

“It's almost like Ireland it's so green out there right now,” state Forester Kirk Rowdabaugh said recently, referring to one area just north of Phoenix. “But we know that's going to turn brown here in a few weeks, and certainly by early May it'll be cured out enough to start to carry fire.”

The conditions are reminiscent of those in 2005, when a blaze named the Cave Creek Complex became the second-largest wildfire in state history. It scorched nearly 250,000 acres of desert and destroyed 11 homes in a small community northeast of Phoenix.

“It looks like the greater Phoenix metro area and for many miles around that has grass growing at this point is going to see some kind of substantial fire season,” said Chuck Maxwell, a fire meteorologist at the Southwest Coordination Center in Albuquerque. “It's going to happen, it's just a matter of how severe it is.”