Weather: Rain is likely over the next 24-hours. Courtesy image

Los Angeles is preparing for a major winter storm after wet weather drenched the northern part of the state on Monday.

Motorists spun out on whitened mountain passes and residents wielded umbrellas that flopped in the face of fierce winds as Northern California absorbed even more rain and snow on Monday, bringing the possibility of rockslides and mudslides to areas scarred by wildfires following an especially warm and dry fall across the U.S. West.

The multiday storm, a powerful “atmospheric river” weather system that is sucking up moisture from the Pacific Ocean, raised the threat of flooding and was expected to dump more than 8 feet of snow on the highest peaks in California and Nevada and drench other parts of the two states before it moves on midweek, forecasters said.

The storm will bring much needed moisture to the broader region that’s been gripped by drought that scientists have said is caused by climate change. The latest U.S. drought monitor shows parts of Montana, Oregon, California, Nevada and Utah are classified as being in exceptional drought, which is the worst category.

Most western U.S. reservoirs that deliver water to states, cities, tribes, farmers and utilities rely on melted snow in the springtime.

This week’s storm is typical for this time of the year but notable because it’s the first big snow that is expected to significantly affect travel with ice and snow on the roads, strong winds and limited visibility, said National Weather Service (NWS) meteorologist Anna Wanless in Sacramento.

“Most of California, if not all, will see some sort of rain and snow,” she said.

The National Weather Service said there’s a slight risk of excessive rain over Southern California Tuesday and into Wednesday morning.

The wet weather developed over the Pacific and swept south throughout the day. Experts said they expect the storm to continue moving south and eventual reach Mexico on Wednesday.

“The moisture will produce coastal rain and higher elevation snow over the Pacific Northwest and Northern/Central California and snow extending eastward to the Northern Rockies through Tuesday,” said NWS.

Officials said heavy rain in the area will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable.

“Impacts will include travel delays, including commute times, potential for debris flows in recent burn areas, localized flooding, mud and rock slides on mountain road, and winter driving conditions in the mountains above 5000 feet,” said the NWS.

County officials are urging residents to be prepared in the event of significant rain, particularly residents who live in areas where debris or mud flows could be a problem.

“Weather experts are telling L.A. County residents to get ready for heavy rain, and communities located near burn scarred terrain may experience flash floods and mud or debris flows,” said Kevin McGowan, Director of the Los Angeles County Office of Emergency Management. “Our emergency response officials are world-class and will stand ready to defend lives, property and infrastructure if there are emergencies caused by this storm. But, we need collaboration from the public. It is critical for residents to be aware and prepared so that they can help keep themselves safe.”

Safety tips:

If you live in a recent burn area:

Acquire any needed sandbags and instructional materials at your local Los Angeles County fire station. Click here for locations near you.

Have an emergency plan in place that is easy for all family members to understand.

Monitor radio and TV news closely for information about weather conditions and flooding in your area.

If an evacuation is ordered, be prepared to leave immediately. Have alternate evacuation routes out of your neighborhood.

If your neighborhood is evacuated, identify important items to take (e.g., computers, photos, important documents, medications, and other essential items for your family and pets).

Have enough food and water to supply your family for at least a 72-hour period.

Always remember to include a radio and flashlight with fresh batteries in your emergency kit.

Be storm smart! Follow these general storm safety guidelines:

Stay away from flood control channels, catch basins, canyons, and natural waterways which are vulnerable to flooding during periods of heavy rain.

Do not attempt to cross flooded areas and never enter moving water on foot or in a vehicle.

If flooding traps you in your vehicle, stay in your vehicle (if possible) and call 9-1-1. If necessary, wait on top of your vehicle for assistance.

If you see someone who has been swept into moving water, do not enter the water and attempt a rescue. Immediately call 9-1-1 and, if possible, throw a rope or some type of flotation device to them.

The Associated Press contributed to this report.