A slow-moving rain system settled into Southern California on Sunday, recovering from a long dry spell but also threatening mudslides in areas scarred by this month’s wildfires.
The rain is expected to continue till Monday afternoon, with intermittent outbreaks of light rain and heavy rain in the region, forecasters said. The rain can reduce fire hazards and help vegetation through the fastest start to the rainy season on record in Los Angeles.
But the National Weather Service also estimated a 10 to 20 percent chance of significant mudslides in several Los Angeles County burn spots, sensitive areas where trees and brush catch fire.
Mark Chanard, a meteorologist with the service, said that in burn scars, the loosened soil can act like a slick pavement when soaked by rain, creating soil flow conditions.
“You don’t get any water absorption,” Mr Chenard said. “It all turns into runoff right away.”
The heaviest rainfall was expected between 4pm on Sunday and 4pm on Monday. According to the service. Los Angeles and Ventura counties were expected to receive up to an inch of rain yesterday, and up to three inches were forecast in the mountains around Los Angeles.
Burn marks include areas A fire gutted the Palisades in the Pacific Palisades section of Los Angeles. Horst fire near the Sylmar area of the city. Sunset Fire near West Hollywood; Eaton Fire near Pasadena; Hughes Fire near Caustic Lake; and the Franklin Fire near Malibu, among others.
The weather service said there was a 5 to 10 percent chance of experiencing mudslides in burn scars outside of Los Angeles County.
Residents were urged to stock up on supplies and protect property with sandbags. A flood watch was in effect for Los Angeles County as of Monday afternoon.
Light rain moved into Ventura County, north of Los Angeles, on Saturday evening and picked up across the region on Sunday, the service said.
The system was flowing southeast through Los Angeles County, providing power and outages in some areas, according to the service. During Sunday afternoon, the heaviest rainfall rates—about three-quarters of an inch per hour—were confined to isolated areas.
Rainfall rates of more than half an inch per hour in the burn marks could cause “some significant problems,” Mr. Chenard warned.
The Los Angeles region endured months of brutal drought, fueling this month’s devastating wildfires, which burned thousands of acres and displaced more than 100,000 people.
John Ferrick, senior meteorologist at EchoWeather, said Saturday that no measurable rainfall had fallen in downtown Los Angeles this year. He termed the rain as a welcome news.
“In general, this is beneficial rain,” Mr. Ferrick said. “That should help the fire situation tremendously.”
“Now, with that comes the risk, because there are burn marks,” he added.
