California wildfires: It's a people problem

By Lisa M. Krieger

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[Stephen M. Strader's] major new analysis, published this spring in the journal Natural Hazards, found a 1,000 percent increase in the number of western U.S. homes at risk from wildfire over the past 50 years – from about 607,000 in 1940 to 6.7 million in 2010.

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While it might seem as if California’s wildfires are increasing, new research by Keeley shows that it is not so.

But they are far more destructive, according to CalFire. Nine of the 10 most expensive fires in California history occurred in the past 20 years.

A big reason why: It’s harder to do controlled burns — one of the most effective fire suppression techniques — near residential areas, due to smoke concerns. Until the 1970’s, fire suppression tended to minimize fire spread.

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And as we develop rural areas, we’re also more likely to ignite fires. In early California history, lightning was the major cause of wildfires. Now humans are the dominant source of fires, due to downed power lines, smoking, sparks from equipment and more.

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