As the deadly Camp and Woolsey fires blaze on either end of California, the state is expected to finally get some rain in the next couple of days ― bringing relief from the flames and unhealthy air pollution, but also a very real danger of mudslides in the burned areas.
The National Weather Service has issued a flash flood watch for the Camp fire burn areas near Paradise, with rains expected to fall across Northern California from Wednesday through Friday. The Camp fire has become the state’s deadliest and most destructive wildfire ever: At least 79 people have died and more than 12,000 homes have burned since it began Nov. 8.
Flash floods and debris flows will be a “particular threat” in the burn areas, the agency said. Residents should “remain alert” as roads could be blocked by flooding, and fire-damaged trees could fall in winds forecast at up to 40 miles per hour.
“This could quickly become a dangerous situation,” the agency warned Tuesday.
In Southern California, the weather service anticipated potential mudslides and “minor debris flows” in the Woolsey fire’s burn areas near Malibu, with rainfall expected Wednesday and Thursday.
The Woolsey fire has killed three people, burned hundreds of homes ― including those of some celebrities ― and spurred mass evacuations of Malibu and surrounding areas. It was almost fully contained by Tuesday.
The NWS warned of “the potential for rockslides and mudslides” causing “significant travel delays on the already very busy holiday” over Thanksgiving ― though it said there was a low probability that enough rain would fall to trigger mud and rock slides.
However, the California Department of Forestry and Fire Prevention (Cal Fire) in Southern California urged residents in burned areas to prepare for possible floods and mud flows, calling these a “very realistic threat” and noting that people should not take evacuation orders “lightly.”
Mudslides are a common risk after wildfires. When land is burned, vegetation that may have held back debris is destroyed, setting the stage for mud flows. Scorched terrain also less easily absorbs rain, with burned soil “as water repellant as pavement,” according to the weather service.