Widespread flash flooding and mudflows have hit Southern California after heavy rain, prompting evacuation orders and warnings for motorists to stay off roads, authorities said.

Emergency services carried out dozens of rescues after vehicles became trapped in floodwaters, particularly in the mountain resort town of Wrightwood, east of Los Angeles, according to the San Bernardino County Fire Department.

No casualties had been reported by Wednesday night, fire department spokesman Christopher Prater said.

Officials issued flash-flood warnings across much of Los Angeles County, urging residents to avoid travel unless under evacuation orders or fleeing flooded areas.

Los Angeles city authorities ordered about 130 homes to evacuate in areas at high risk of mudslides and debris flows, particularly in parts of Pacific Palisades affected by last year’s wildfires.

The storm was driven by an atmospheric river, a narrow band of dense moisture drawn from the Pacific Ocean, producing rainfall of up to an inch (2.54cm) an hour in parts of the greater Los Angeles area, the U.S. National Weather Service said.

Forecasters warned that “life-threatening” conditions were expected to persist through Christmas Day, with unsafe driving conditions during what is typically a busy holiday travel period.

Strong winds accompanying the storm downed trees and power lines, while heavy snow was forecast at higher elevations in the Sierra Nevada.

Meteorologists also issued a rare tornado warning for parts of east-central Los Angeles County amid severe thunderstorms over Alhambra.

Rainfall eased by Wednesday night, but forecasters said a second wave of the storm system was expected to move through the region on Thursday.

Tags

Los Angeles California Storm Flash flooding Southern California Climate Impact