Heavy rain poured on the Southland Thursday, prompting mudslides, debris flows and flooding that made for a messy morning drive that was fortunately light due to the approaching holiday weekend.

Snowfall forced the closure of Interstate 5 through the Grapevine early Thursday morning in northern Los Angeles County, while a mudslide blocked traffic and trapped some vehicles on Coldwater Canyon Avenue in Studio City, and flooding blocked the westbound Santa Monica (10) Freeway near the McClure Tunnel in Santa Monica.

In Malibu, more than four dozen people had to be evacuated from Leo Carrillo State Beach campground due to flooding, which also led to closures on Pacific Coast Highway. Decker Road was closed at PCH due to multiple rockslides, according to the city, which also reported multiple instances of downed trees blocking roadways. PCH was also closed at Puerco Canyon due to flowing mud.

A stretch of PCH was closed in Pacific Palisades due to a fallen tree that brought down power lines, according to Caltrans.

Overnight, Mulholland Highway was closed in the Santa Monica Mountains between Las Virgenes and Cornell roads due to mud that inundated the roadway.

Downpours were expected to continue throughout the morning, with the rain anticipated to taper off in the afternoon, giving way to a dry but cool weekend. Around mid-morning, forecasters said they were still monitoring the path of the storm, but parts of Los Angeles County could still get another 2 to 4 inches of rain before the system exits the area.

“All considered, there’s still the risk of higher (rainfall) rates and the potential for mud and debris flows from the recent burn areas of L.A. County,” according to the NWS.

Parts of the Santa Monica Mountains had already received between 3 and 5 inches of rain by Thursday morning, with 2 to 3 inches falling in surrounding areas, the weather service reported.

A winter storm warning will be in effect until 8 p.m. Thursday in the Los Angeles County mountains, excluding the Santa Monica range. The National Weather Service said 1 to 3 feet of snow was expected to accumulate above 5,000 feet, with “light snow” falling at lower elevations. Winds were also gusting in the area, with the NWS saying 45 to 50 mph sustained winds were anticipated, with higher-elevation gusts of up to 60 mph.

“Travel could be very difficult to impossible,” according to the NWS.

According to the NWS, roughly 18 inches of snow had already fallen in the eastern San Gabriel Mountains by mid-morning Thursday, with 3 to 6 inches falling in Frazier Park

Stretches of Angeles Crest Highway were closed due to the poor weather conditions, along with state Route 39.

Caltrans reminded motorists that chains were required on the Angeles Crest Highway north of La Canada Flintridge, and the agency urged motorists to be aware of road conditions and anticipate possible closures due to snow.

Gusting winds were also impacting the Antelope Valley, where the NWS issued a wind advisory through 10 p.m. Forecasters said the area should expect winds of 15 to 30 mph, with gusts up to 45 mph, potentially reducing visibility for motorists and blowing dust across roadways.

In Orange County, a mandatory evacuation order that was in effect for the Silverado, Williams and Modjeska canyon areas in the Bond Fire burn area due to fears of possible debris flows was downgraded Thursday morning to voluntary. Streets in the area that were closed overnight were reopened to local traffic only.

The NWS issued a flash flood watch for Orange County coastal and inland areas and the Santa Ana Mountains, including the Bond Fire burn area. The watch was expected to be in effect through Thursday afternoon, but it was canceled by midday, with forecasters saying flooding “is no longer expected to pose a threat.”

NWS forecasters for Orange County said the area could receive up to 2.5 inches of rain along the coast and as much as 6 inches in the mountains below 5,000 feet, with hourly rainfall amount of 0.6 to 0.7 inches possible.

A flash flood watch will continue until 4 p.m. for Los Angeles County burn areas from the Lake, Bobcat, Dam and Ranch 2 fires.

“Heavy rainfall could trigger flash flooding of low-lying areas, urbanized street flooding and debris flows in and near recent wildfire burn scars,” according to the NWS.

“By (Thursday), the steadier precipitation should hang on over LA County through at least the morning hours then become more showery in the afternoon,” forecasters said.

Temperatures will also remain “significantly below average” across the region, according to the NWS.

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