USA — Each year, the tacticsand technology developed to combatwildfires are put to the test as fast-movingwalls of flames tear through the nation’s forests, scorching record numbersof U.S. acres. Indeed, this week’s dozen or so wildfires blazing across SouthernCalifornia are a grim reminder that technology is a poor match for MotherNature, which seems to have the ultimate say in how long these infernos last andhow much devastation they reap.
Photo courtesy of the U.S. Department of the Interior
In Southern California, winds were easing, but “major blazes burnedunchecked for a fourth day after forcing the largest evacuation in California’smodern history,” Reutersreported. About 1,300 homes had been destroyed in San Diego County alone andexperts put damages at more than $1 billion. More than 500,000 people have beenforced to flee their homes.
The BBC reportsthat firefighters are finally making headway against the stubborn flames–whichby late afternoon Wednesday had spread 470 square miles (1,214 sq kilometers)across seven counties–by dumping water and chemical fire retardants from theair onto the parched brush.
Image courtesy of the U.S. Department of the Interior
In “PredictingWildfires” (Scientific American, August 2007), writers PatriciaAndrews, Mark Finney and Mark Fischetti report that the number of catastrophicwildfires in the U.S. has been steadily rising in recent years. “The nationhas spent more than $1 billion annually to suppress such fires in eight of thepast 10 years,” they write. “In 2005 a record 8.7 million acres burned,only to be succeeded by 9.9 million acres in 2006.”
The article poses a number of important questions. Among them: Was too muchfuel (in the form of tinder-dry deadwood, underbrush and debris) allowed tocollect in certain areas, particularly those close to the residences nowengulfed by the fire? “Forests harbor more fuel than ever in large partbecause for decades, land management agencies, including the U.S. ForestService, have followed a policy of trying to quickly put out every fire thatstarts,” the article says.
It also calls into question whether anything can be done to mitigate the riskof these catastrophic events as well as the amount of damage they cause. In arelated article, Finney proposes that, if fires are not permitted to burn, fuelsaccumulate across vast contiguous tracts: deadwood piles up, brush and new treesgrow in thick, and tree canopies become dense. “When a fire does ignite,”he writes, “there is so much fuel across such a wide area that no level offirefighting can contain it, causing severe consequences.”
Finney suggests that “certain fires that start naturally–or portions ofthem–should be allowed to burn,” with firefighters on hand to protecthomes, power lines, watersheds and other important properties. Also, “moreprescribed burning should be pursued” and “some brush, low-hangingtree limbs and small trees must be thinned, especially in places where peoplelive and work.”
In addition, regions vulnerable to wildfires should plan ahead to limit loss.”Right now meteorologists and fire behavior analysts in the PredictiveServices program, managed by the National Interagency Coordination Center (NICC)in Boise, Idaho, issue maps of weekly, monthly and seasonal outlooks of wherethe potential for fire is greatest,” the authors say. The maps are based onWildland Fire Assessment System (WFAS) projections, but other factors, such aslong periods of parched soil that can result in dry trees, that are hard to pindown must be woven in as well.
A key point the authors make: “Regardless of progress, fires will alwayshappen.” The key to gettingthe upper hand: Take steps to limit the risk and be prepared when and ifthey strike.