This holiday season, California is bracing for a deluge, with meteorologists predicting up to eight inches of rain in regions such as Los Angeles County and Santa Barbara over the coming days.

State officials are advising travelers to stay off the roads as a series of winter storms bring threats of flash flooding and even tornadoes.

The storms started rolling in on Tuesday night and are expected to gather strength through Christmas Eve. A ‘clipper’ weather pattern is anticipated to drench the West Coast and Midwest with rain and snow on Christmas Day.

Los Angeles is facing a significant impact, with a severe flood warning active until noon on Wednesday. Residents in vulnerable areas have been instructed to evacuate and seek higher ground immediately.

With millions planning to travel across California for the holidays, authorities warn of potentially treacherous conditions as multiple atmospheric rivers are expected to sweep through the state.

“If you’re considering road travel for the Christmas holidays, please rethink your plans,” urged Ariel Cohen, a National Weather Service meteorologist in Los Angeles, during a press briefing on Tuesday.

Forecasters said Southern California could see its wettest Christmas in years and warned about flash flooding, mudslides and debris flows in areas scorched by last January’s wildfires. 

Los Angeles is expected to be especially hard hit by the incoming winter storms, with a severe flood warning in place for the area until 12pm on Wednesday. Hundreds of residents in at-risk neighborhoods have been warned to ‘immediately move to higher ground’

The holiday period is forecast to be a washout for the Golden State this year, with meteorologists warning that up to eight inches of rain is expected to hit several areas including Los Angeles County and Santa Barbara (Pictured: Menlo Park, CA, on December 24)

Los Angeles County officials said they were knocking on the doors of some 380 particularly vulnerable households to order them to leave. 

Much of the Sacramento Valley and the San Francisco Bay Area were under a flood watch and a high wind warning through Friday.

Forecasters warned heavy snow and gusts were expected to create ‘near white-out conditions’ Wednesday in parts of the Sierra Nevada and make it ‘nearly impossible’ to travel through the mountain passes.

There’s also a risk of severe thunderstorms and a small chance of tornadoes along the northern coast.

Heavy rain and flash flooding already led to water rescues and at least one death in Northern California, local officials said. 

Shasta County Sheriff Michael L. Johnson on Monday declared a state of emergency to prepare for more rain and allow the state to help with hazard mitigation and search and rescue operations.

Southern California typically gets half an inch to 1 inch (1.3 to 2.5 centimeters) of rain this time of year, but this week many areas could see between 4 and 8 inches (10 to 20 centimeters), National Weather Service meteorologist Mike Wofford said. 

It could be even more in the mountains. Gusts could reach 60 to 80 mph (96.5 to 127.8 kph) in parts of the central coast.

A powerful storm is turning roads into rivers while triggering torrential mudslides as apocalyptic scenes sweep southern California on Christmas Eve. (Pictured: A view of a flooded street close to the Meta Campus during the downpour in Menlo Park, CA, on December 24) 

Storms began to move in late Tuesday evening and were expected to intensify throughout Christmas Eve, while a ‘clipper’ weather system is due to submerge much of the West Coast and Midwest in rain and snow on Christmas Day. (Pictured: Menlo Park, CA, on December 24)

Officials expect multiple road closures and airport delays during the storms. Downed trees and power lines are also possible. Parts of Los Angeles are under evacuation warnings this week.

The county put up K-rails, a type of barrier, around the burn scar to help catch sliding debris during rainstorms. 

Residents could also pick up free sandbags to protect their homes, said Kathryn Barger, a Los Angeles County supervisor representing Altadena.

Many people in burn scar areas decided not to leave after receiving the evacuation notification, Los Angeles Police Department Chief Jim McDonnell said. He urged them to reconsider.

‘The threat posed by this storm is real and imminent,’ he said.

Local and state officials are gearing up to respond to emergencies through the week. 

The state has deployed resources and first responders to a number of counties along the coast and in Southern California. The California National Guard is also on standby to assist.

An atmospheric river is a long, narrow band of water vapor that forms over an ocean and flows through the sky, transporting moisture from the tropics to northern latitudes.