Southern California is bracing for another round of powerful storms as officials confirmed Saturday a third body was found after a series of avalanches in the state.

Two skiers were killed after three avalanches swept backcountry slopes in the San Gabriel Mountains on Friday. A snowboarder was found safe on Saturday, while police confirmed a third body was discovered later in the day.

Angeles National Forest spokesman Stanton Florea told The Associated Press an avalanche advisory was issued for the ski area at nearby Mount Baldy located about 64 kilometres from Los Angles.

In northern California, the Sierra Avalanche Center in Truckee issued an advisory on Saturday as increasing southwest winds redistribute snow that fell over the past week, increasing slab formations that threaten to give way.

"Near and above treeline, human triggered avalanches are possible to probable today," the centre's website reads, adding that natural avalanches are also possible in areas with heavy winds.

Meanwhile, flash flood warnings and winter storm watches have been issued throughout the state.

The latest winter storm is expected to bring heavy rainfall and flooding to most of southwestern California as a deep low-pressure system over the eastern Pacific will tap into a subtropical jet stream, the U.S. National Weather Service reported Saturday.

A flash flood watch has been issued for all of Santa Barbara, Los Angles counties, the San Diego County Mountains, Santa Monica Mountains, Ventura and other areas across the state.

Residents of four Orange County canyons are being urged to comply with a voluntary evacuation order issued because of possible mudslides.

"Recent storm events leading up to this storm system have already saturated soils and provided runoff into area streams. In addition, significant lingering snowpacks of two feet or more in the mountains and even several inches at lower elevations will add to the runoff into smaller streams and rivers during the next storm," the U.S. weather services said on its website.

A winter storm watch has been issued for the Los Angles Country Mountains, Burney Basin, the San Bernardino County Mountains and Eastern Shasta County as heavy snow is expected to fall causing poor visibility in combination with high winds.

The weather office has also issued a coastal hazard message as gale-force southeast winds will cause dangerous rip currents and surf building more than two metres high along the beaches of southern Santa Barbara and other coastal areas.

The series of storms has already caused considerable damage and delayed travellers in the state earlier this week.

On Friday, a Metrolink train hit a slide of mud during the morning commute in Friday in Los Angeles. The train was pulled free by another train as passengers were delayed for two-and-a-half hours, Metrolink spokeswoman Denise Tyrrell told the AP.

Flights were delayed up to two hours Friday at the San Francisco International Airport while residents in the Marin County towns of San Anselmo and Fairfax were asked to leave their homes and businesses because of flooding from a nearby creek.

With files from The Associated Press