California’s worst wildfires a mystery
Causes of several blazes still elude authorities
California officials quickly determined an arsonist started last month’s huge wildfire southeast of Los Angeles, and that two weeks earlier sparks from a vehicle produced a deadly wildfire in the far northern part of the state.
But causes for many of California’s worst blazes of the past decade remain a mystery.
The Associated Press reviewed state data on the 10 largest wildfires and 10 most destructive in terms of homes and buildings burned for each year dating to 2008. Lightning was the most common cause, accounting for about a quarter of those fires, followed by incidents involving power lines.
However, investigators could not determine a cause for about a third of those fires. Experts say each is a missed opportunity to learn something new.
“If we don’t know what causes a fire, we don’t know how to prevent them,” said Carrie Bilbao, a spokeswoman for the National Interagency Fire Center who investigated wildfires in Idaho for 26 years.
Finding the trigger aids criminal prosecutions and helps determine liability. It also guides campaigns to change behavior, like avoiding mowing on hot afternoons when fire threat is high. And it leads to safety enhancements, like sleeves on power lines, which came about when it was determined that falling tree branches and birds cause sparks when they hit unprotected electrical wires.
It’s estimated human activity — from untended campfires to sparks from vehicles — causes more than 80 percent of all wildfires in the United States, according to the National Interagency Fire Center.