A slow-moving rainstorm system was bringing a reprieve to Southern California on Monday after a lengthy dry spell, but also caused some mudslides in areas scarred by this month’s wildfires, forcing road closures and making driving hazardous.
The storm had dropped about half an inch of rain in downtown Los Angeles by early Monday morning, the most the city has received in about nine months. The rain was easing, and the threat of flooding and mudslides was expected to decrease as the day went on, though some isolated showers were expected into Tuesday.
The precipitation had caused some damage and hazards. The Los Angeles Fire Department said there had been “debris flow” and “vehicles in the mud” in Woodland Hills overnight. Local news media showed images of mudslides in Pacific Palisades.
The Santa Monica-Malibu Unified School District said its schools in Malibu would be closed on Monday because of dangerous road conditions and challenges accessing the schools. Schools in nearby Santa Monica remained open.
Snow in the Tejon Pass, northwest of Los Angeles, forced the closure of a portion of Interstate 5 on Sunday evening, California’s Department of Transportation said. The highway remained closed as of 6 a.m. Pacific on Monday.
Part of Canyon Boulevard at Pacific Coast Highway was also closed for safety, the Department of Transportation said. Topanga Creek overflowed, scattering debris across the boulevard, the agency said on social media.
The National Weather Service had warned of a 10 to 20 percent chance of significant mudslides in several Los Angeles County burn scars, sensitive areas where fires burned through trees and brush.
In the burn scars, the charred soil could act like slick pavement when soaked by rain, creating the conditions for mudslides, said Marc Chenard, a meteorologist with the service.
“You just don’t get any absorption of the water,” Mr. Chenard said. “It just all immediately turns into runoff.”
The burn scars include areas scorched by the Palisades fire in the Pacific Palisades section of Los Angeles; the Hurst fire near the Sylmar area of the city; the Sunset fire near West Hollywood; the Eaton fire near Pasadena; the Hughes fire near Castaic Lake; and the Franklin fire near Malibu, among others.
Burn scars outside Los Angeles County had a 5 to 10 percent chance of experiencing mudslides, the Weather Service said. Residents were urged to stock up on supplies and protect property with sandbags.
The Los Angeles region had endured a brutal drought for months, feeding this month’s devastating wildfires, which burned across thousands of acres and displaced more than 100,000 people.
The two largest fires were nearly contained on Monday morning, with the rain further helping firefighters. The largest blaze, the Palisades fire near Malibu, was 90 percent contained, and the Eaton fire was 98 percent contained, according to Cal Fire.
Before Saturday, there had been no measurable rain in downtown Los Angeles this year, said John Feerick, a senior meteorologist at AccuWeather. He described the rain as welcome news.
“In general, this is beneficial rain,” Mr. Feerick said. “It should help with the fire situation immensely.”
“Now, with that comes the risk, because there are burn scars,” he added.
Claire Moses and Judson Jones contributed reporting.
