An unusually strong storm system has reached Southern California, raising fears that the rain could unleash a threat that has been lingering in the burn scars of wildfires that ravaged Los Angeles communities in recent years.
Called debris flows, these fast-moving slurries of floodwater and sediment can hurtle down slopes carrying cars, trees and even boulders with them.
They’re like “a flood on steroids,” said Jason Kean, a research hydrologist with the U.S. Geological Survey’s landslide hazards program. “It’s really hard to stop these things. The best thing to do is get out of the way.”…