A winter storm warning will be in effect until 4 a.m. Wednesday for the Los Angeles County Mountains, excluding the Santa Monica Range, the National Weather Service announced.
Heavy snow is forecast, with additional snow accumulations of 8 to 14 inches for elevations above 7,000 feet through early Wednesday, with 2 to 4 inches possible at 4,000 feet, including Interstate 5 near the Grapevine.
Lighter snow accumulations will be possible as low as 2,500 feet. Periods of south to southwest wind gusts between 35 and 45 mph are expected.
Drivers are cautioned to be prepared for significant reductions in visibility. The Interstate 5 Tejon Pass/Grapevine area will likely see delays due to periods of snow late Monday evening through Tuesday night.
The Antelope Valley (14) Freeway through Soledad Canyon could also be impacted with snow.
A winter storm warning for snow means severe winter weather conditions will make travel very hazardous or impossible. Anyone who must travel, is advised to keep an extra flashlight, food and water in their vehicle in case of an emergency.
Rain fell on much of Los Angeles and Orange counties Monday, prompting a flash-flood warning for the Woolsey Fire burn area in Malibu.
The showers, expected to last through Tuesday, could bring up to 2 1/2 inches of rain in the San Gabriel Mountains and foothills, according to the National Weather Service.
Road closures as of 8:30 p.m. included:
— state Route 23 from Pacific Coast Highway to upper Mulholland Highway in Malibu;
— the truck lanes of southbound Antelope Valley (14) Freeway to the southbound Golden State (5) Freeway; and
— the connector from the northbound San Diego (405) Freeway to the westbound Ronald Reagan (118) Freeway.
Trabuco Canyon Road at Trabuco Creek was closed due to a flash flood downstream of the Holy Fire burn area, Orange County Public Works announced. The department says the force of the fast-moving water moved k-rail barriers, which each weigh about 8,000 pounds.
The flash flood warning for the Woolsey Fire burn area warning expired at 11:45 a.m.
Cooler temperatures accompanied the precipitation, leading to possible snowfall in the Grapevine area late Monday into early Tuesday and “maybe even a dusting in the Antelope Valley foothills,” weather service meteorologist Curt Kaplan said.
The San Gabriel Mountains could see 8 to 16 inches of snowfall above 6,500 feet before the system moves out, he said.
The showers should move out late Tuesday into Wednesday, with the next chance of rain Friday evening into Saturday, Kaplan said.
Winds reached 51 mph in the Santa Monica Mountains Recreational Area and 39 mph in the Santa Clarita Valley.
Los Angeles County rainfall totals included 1.02 inches in Northridge; .90 of an inch in Burbank; .84 of an inch in Pasadena; .77 of an inch at the Getty Center; .36 of an inch at Los Angeles International Airport; and .26 of an inch in downtown Los Angeles.
Orange County rainfall totals included .76 of an inch in Lake Forest; .65 of an inch at John Wayne Airport; and .45 of an inch in Yorba Linda.