CASTAIC (CBSLA) – A powerful storm hit the Southland late Christmas evening and continued into Thursday morning, dumping snow in the mountains, shutting down the Grapevine and the Cajon Pass, and pummeling lower elevations with heavy rain.

Snow near the 15 Freeway in the Cajon Pass. Dec. 26, 2019. (CBS2)

The Grapevine remained closed as of 11:30 a.m. Thursday. The northbound side was closed at Parker Road in Castaic, while the southbound side was closed at Grapevine Road.

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CHP reported Wednesday night that 150 cars and trucks had gotten stuck on the 5 Freeway at Halsey Canyon in over an inch of snow that rapidly turned to ice.

From 5:30 a.m. on, the 15 Freeway over the Cajon Pass was also intermittently shut down in both directions between the Cajon Junction to Hesperia. Caltrans was advising drivers to avoid the freeway if at all possible. Video showed northbound traffic backed up for miles.

The 138 Freeway was also closed between the 15 Freeway to Beekley Road. Chains were required on all mountain routes in San Bernardino and Riverside counties.

The Angeles Crest Highway (State Route 2) in the Angeles National Forest was shut down indefinitely between Newcomb’s Ranch and Highway 39 due to heavy snow and fallen trees.

Thousands of Angelenos were also without power. By 8 a.m., more than 6,670 L.A. Department of Water and Power customers in Echo Park, Silver Lake and East Hollywood were without power, including another 720 customers in Bel-Air.

Near whiteout conditions in Big Bear Valley. (Photo: San Bernardino County Sheriff’s Capt. Mitch Dattilo/Twitter)

The brunt of the storm hit about 9 p.m. Wednesday and was set to remain into the early afternoon Thursday, National Weather Service Meteorologist Kristin Stewart said.

“The system is pivoting on itself,” Stewart said. That means the rainfall could remain in the area longer than originally forecast.

The Angeles Highway. Dec. 26, 2019. (Caltrans)

A winter storm warning remained effect until 10 p.m. Thursday for the L.A. County mountains, excluding the Santa Monica Mountains.

The blustery winds brought on by the storm caused several trees and a lamp post to topple in Ventura Harbor, as well as flooding a hotel parking lot. A large tree also came crashing down onto an apartment building entrance in Woodland Hills.

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Los Angeles Fire Department crews had to use an inflatable boat to rescue a man who got trapped in the L.A. River in the Sepulveda Basin area of Sherman Oaks.

Heavy rain caused issues for morning commuters throughout the L.A. metro area. Several freeways in L.A. experienced flooding overnight. The northbound 5 Freeway, south of the 110 Freeway in Lincoln Heights, was blocked for several hours due to flooding. Throughout the early morning the CHP issued SigAlerts shutting down lanes on the 710 and 14 freeways to allow flooding to subside.

The NWS reported that the deluge resulted in record-breaking rain in Long Beach on Christmas Day, with 1.03 inches through midnight.

Snow in Wrightwood, Calif. Dec. 26, 2019. (Credit: Rinchiuso family)

When it’s all said and done, there could be 1-2 inches of rain in most areas during the storm, Stewart said. The San Gabriel Mountains and foothills could get up to 4 inches of rain.

Snow levels dropped to 2,500 feet and accumulations of 1-2 feet at resorts and 6-12 inches around the Grapevine were expected. Even Lancaster and Palmdale in the Antelope Valley could get snowfall. Six to 10 inches of snow were likely in the Antelope Valley foothills and 3 to 6 inches on the Antelope Valley floor, the NWS said.

A wind advisory remained in effect until 10 p.m. Thursday. Winds of 15-25 miles per hour are forecast in downtown L.A. with gusts of 40 to 50 mph and mountain gusts could hit 50 to 60 mph.

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(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)