Rain helps Southern California firefighters but sends ash and mud flowing down hillsides

In neighboring Malibu, four schools were closed Monday "due to dangerous road conditions and challenges with access," the Santa Monica-Malibu Unified School District said in a statement.

North of Los Angeles, snowy conditions late Sunday shut down the mountainous Tejon Pass section of Interstate 5, a key north-south artery. It remained closed Monday and the California Department of Transportation said there was no estimated reopening time.

A winter storm warning remained in place until 4 p.m. Monday for mountains across San Bernardino and Riverside counties, where more than a foot (0.30 meters) of snow was predicted from the weekend storm. Chains for traction control were required for some vehicles heading to ski resorts in the Big Bear Lake area northeast of Los Angeles.

Flood watches were in effect for the Palisades, Altadena and Castaic Lake areas, said Joe Sirard, a meteorologist for the National Weather Service's office for Los Angeles.

"All these fresh burns are very susceptible to rapid runoff," Sirard said Sunday.

Los Angeles International Airport reported just under an inch of rain (2.5 centimeters) in 24 hours ending at 3 a.m. Monday, the National Oceanic and Atmospheric Administration reported. Surrounding areas experienced lesser amounts.

The rain began Saturday after months of dry and often gusty weather that created dangerous fire conditions. The downpours were a boon for firefighters but created the risk of toxic ash runoff.

Los Angeles County crews spent much of last week removing vegetation, shoring up slopes and reinforcing roads in areas devastated by the Palisades and Eaton fires, which reduced entire neighborhoods to rubble and ash after breaking out during powerful winds on Jan. 7.

The Palisades Fire, the largest of the blazes that destroyed thousands of homes and killed at least 11 people, reached 94% containment Monday. The Eaton Fire, which broke out near Altadena and has killed at least 16 people, was 98% contained.

The Hughes Fire, which ignited north of Los Angeles last week and caused evacuation orders or warnings for more than 50,000 people, was nearly contained.

Downpours in San Diego County, helped firefighters make significant progress against the smaller Border 2 Fire churning through a remote area of the Otay Mountain Wilderness near the U.S.-Mexico border.

A White House statement on Friday said President Donald Trump has directed federal officials to help Southern California with clearing wildfire burn areas. Within five days of the order, the Federal Emergency Management Agency and other departments "shall develop and execute a plan to expedite the bulk removal of contaminated and general debris," the statement said.

City and county officials last week expedited cleanup efforts and other measures aimed at mitigating the environmental impacts of fire-related pollutants.

Officials cautioned that ash in recent burn zones was a toxic mix of incinerated cars, electronics, batteries, building materials, paints, furniture and other household items. It contains pesticides, asbestos, plastics and lead. Residents were urged to wear protective gear while cleaning up.

Concerns about post-fire debris flows have been especially high since 2018, when the town of Montecito, up the coast from Los Angeles, was ravaged by mudslides after a downpour hit mountain slopes charred by a huge wildfire. Hundreds of homes were damaged and 23 people died.

The rain ended a near-record streak of dry weather for Southern California. Most of Southern California is currently in "extreme drought" or "severe drought," according to the U.S. Drought Monitor.