Torrential rains unleashed widespread flash flooding and mud flows across Southern California on Wednesday, as authorities warned motorists to stay off roads while urging residents in flood zones to evacuate or shelter in place.

A sweeping flood watch stretching more than 800 miles along California’s coast and interior plains is in effect this week atmospheric rivers move through.

Strong winds and rain brought misery to California on Wednesday, with downed trees, flooding and intermittent power outages reported across the state. Multiple counties, especially in Southern California, are under flash flood warnings after an atmospheric river dropped inches of rain in the region.

Southern California drivers were urged to stay off the road as conditions deteriorated thanks to downpours fed by an atmospheric river. Interstates were shut down by high water, and evacuation warnings were issued by the San Bernardino County Fire Department.

Forecasters said heavy rain was expected to drench much of Southern California through the holidays, and officials warned the storm could be deadly.

Southern California's coastal areas and valleys are forecast to get anywhere from 4 to 6 inches of rain from Tuesday through Saturday. Much of Southern California also is under a high-wind watch.

The winter storm brought heavy rain, flooding, and road closures across California. Officials evacuated people, closed major roads, and declared a state of emergency., US News, Times Now

Floodwaters swept Shasta County on Sunday, killing at least one person. Forecasters warned that Central California would receive heavy rain later in the week.