Heavy rain forces road closures amid mudslide risks in fire zones
- Share via
Heavy rain pelted parts of Los Angeles County early Monday, causing a flash flood advisory to be issued over a wide swath of the region after midnight.
As workers prepared for their Monday morning commute, they were met with the 5 Freeway through the Grapevine being shut down due to snow and no estimate on when it would reopen. The 101 Freeway in downtown was reopened at 6 a.m. after being closed for flooding.
Pacific Coast Highway in Malibu was also closed, along with several other canyon roads including Topanga Canyon.
Between one-fifth of an inch and 1 inch of rain has fallen so far across the region since the storm began Saturday night, and an additional one-tenth of an inch to half an inch is expected.
Mud, rock and debris flows, which forecasters say could affect roads and homes in and below the burned areas, continue to be a concern through Monday as heavy, localized rainfall is possible.
In the eastern part of L.A. County, bouts of heavy downpours and hail were still possible through Monday morning, the National Weather Service said. But the biggest concerns remain on the hillsides.
A debris flow can happen when water rapidly moves downhill and picks up mud, rocks, branches and sometimes massive boulders, capable of crushing cars and homes, and potentially threatening lives. Debris flow are a risk after wildfires because the heat of the fire makes the soil repellent to water, which doesn’t percolate as well into the soil and instead can move objects fast downhill.
Flash-flood and mudslide risks for the burn areas had mostly diminished early Monday, forecasters say. Here are some rain totals.
A flood watch is set to continue through 4 p.m. Monday for the burned areas of the Eaton fire in the Altadena and Pasadena areas; the Palisades and Franklin fires in the Pacific Palisades and Malibu areas; the Hughes fire around Lake Castaic; and the Bridge fire in the San Gabriel Mountains west and southwest of Wrightwood.
The weather service said there’s a 10% to 20% chance of significant flash flooding and debris flows capable of damaging roads and homes in and around areas devastated by wildfires. It’s enough of a risk to prepare for a worst-case scenario, forecasters said.
On Sunday evening, a flash flood warning was in effect for the Franklin fire burn scar and a portion of the Palisades fire burn area.
Radar and rain gauges indicated thunderstorms were “producing heavy rain across the warned area,” which includes Malibu; Malibu Creek State Park, which is near Calabasas; and Malibu Canyon and Las Virgenes roads through the Santa Monica Mountains.
Rainfall rates of 0.39 of an inch per hour were reported near Pepperdine University around 8:15 p.m., the weather service said. A rate of half an inch per hour or more is the point at which a debris flow could be triggered in burned areas, forecasters say.
In this section of western Altadena, residents weren’t ordered to evacuate until after 5 a.m., according to records reviewed by The Times. That was well after smoke and flames were threatening the area.
Reports of mudslides and debris flows trickled in Sunday evening. Officials at a Pacific Palisades town hall said the Los Angeles Fire Department was working to remove mud that had accumulated on Palisades Drive on Sunday evening and that black ash-laden water had reached the beach. KABC-TV News captured residents working to free vehicles trapped in mudslides in Woodland Hills.
Just before 5 p.m., the California Department of Transportation announced mudslides in Topanga Canyon had prompted the closure of a section of Pacific Coast Highway. At 8:15 p.m., flooding was reported along the highway, the service said.
At 8 p.m., the Santa Monica-Malibu Unified School District announced it was closing all four of its Malibu schools Monday due to dangerous road conditions and challenges accessing the schools.
As the storm brought heavy, localized rain Sunday, the weather service temporarily issued higher-level flood advisories for larger swaths of Southern California, indicating flooding is occurring, imminent or likely.
After an epic dry streak, the first real rain of winter fell in Southern California, bringing elevated risk of floods and landslides to areas recently burned by wildfires.
Between 6 and 11 p.m., the service issued a flurry of advisories for L.A., Santa Barbara and Ventura counties, encompassing the Palisades, Franklin, Kenneth and Mountain burn scars.
Sign up for Essential California
The most important California stories and recommendations in your inbox every morning.
You may occasionally receive promotional content from the Los Angeles Times.
