It has the potential to be a snowmaker of epic proportions: A brutal winter storm moving through California is slated to drop rain, sleet and snow from the Oregon border down to the deserts near Mexico.

Forecasters say “all eyes” are on Thursday through Saturday, when even Southern California could see several feet of fresh powder in the mountains around Los Angeles. The National Weather Service has issued a blizzard warning in the L.A. and Ventura County mountains — only the second time such a warning has been issued, following a similar storm in 1989.

“It’s bringing all of that cold air down to Southern California — we’re getting the full brunt,” said meteorologist David Sweet of the incoming system.

Temperatures were expected to be as much as 20 degrees below normal, and by Wednesday afternoon, snow was already starting to fall in portions of the Antelope Valley, while hail was pounding the pavement in Highland Park and Pasadena. Residents reported a dusting of snow in La Crescenta, and 50 mph gusts battered Thousand Oaks and Agoura.

“It’s got the cold air, it’s got the moisture, it’s got strong winds,” said Sweet, who works with the weather service in Oxnard. “It’s an ideal situation for a big weather maker with huge impacts.”

In the Los Angeles area, snowfall totals at 4,500 feet elevation or higher could be as much as 5 feet, with some isolated instances of up to 8 feet of snow, according to forecasters. Areas with elevations from 2,500 to 4,000 feet — including the Tejon Pass — could see as much as 12 inches of snow, while areas at 1,500 to 2,500 feet could see up to 4 inches, including the Antelope Valley.

The weather service also issued a flood watch for large swaths of Ventura and Santa Barbara counties, where as much as 5 inches of rainfall is possible between Thursday night and Saturday afternoon.

This week’s storm is unusual even in a winter of unusual events, climate experts say.