CHILLY WEATHER BRINGS FROST WARNING.

Byline: Staff and Wire Services

Skies cleared rapidly across Southern California's snow-swept mountains Monday afternoon, but that set the stage for subfreezing Antelope Valley temperatures overnight and potentially perilous driving conditions.

A frost advisory will be in effect in the High Desert from Victorville to the Grapevine - where the mercury likely will dip into the 20s - into this morning, according to the National Weather Service.

Isolated showers also remain a possibility today in the Antelope Valley, with a few more flurries in the mountains, including Wrightwood, where up to 3 feet of snow accumulated since Saturday night.

Across the Los Angeles Basin and the San Fernando Valley and Ventura County, the forecast through the holiday weekend calls for partly cloudy or clear skies, with highs in the 60s and lows in the 40s, the NWS said.

The heavy weekend snowfall across Southern California mountains stranded a group of campers Monday in the San Bernardino National Forest community of Idyllwild, where at least two feet of snow made the road down impassable, authorities said.

Crews were using bulldozers late Monday to try to clear the road leading up the Santa Rosa Peak area to the approximately 10 campers, said Sgt. Earl Quinata of the Riverside County Sheriff's Department.

In the Angeles National Forest, three inches of snow was reported at Mount Wilson at 5,300 feet, and 18 to 24 inches fell at Mount Waterman, according to the NWS.

Three to four feet of snow was reported at Mount Baldy, south of Wrightwood, in western San Bernardino County. And in Apple Valley, residents got a dusting of snow, which it rarely sees at 1,000 feet above sea level.

Snow also was reported in the Antelope Valley. In Llano, close to the northern base of the mountains, and near Lancaster 9 inches of snow was reported.

Farther south at Acton, transplanted resident Victoria Berding said she walked outdoors and was greeted by snow.

``It was beautiful,'' she said. ``It reminded me of home'' in Iowa and Minnesota.

Even farther south, near the Los Angeles Civic Center, overnight lows are expected to be in the 40s.

``A cold upper-level low-pressure system that brought numerous snow showers to the mountains and Antelope Valley foothills has started to move east out of Southern California,'' the National Weather Service reported Monday afternoon, after allowing a winter weather advisory in the higher elevations to expire.

Due to icy conditions, however, motorists still are urged to slow down and allow extra time to reach their destination tonight.