Atmospheric River To Lash California As Warnings Issued to Residents

A dangerous storm is set to bring heavy rain and "life-threatening" flooding to California in the coming days, forecasters warned.

The storm is the second time this week that an atmospheric river, a long band of moisture that forms over the Pacific Ocean, has dumped several inches of rain across parts of California.

This storm—expected to be worse than the one earlier in the week—will bring "impactful and dangerous flooding rains, heavy snow, strong winds, coastal flooding, and high surf" to California over the next couple of days, the National Weather Service (NWS) said in a forecast early Sunday.

Much of the state was under some kind of wind, surf or flood watch or warning by Sunday morning.

The weather service forecasts 3 to 6 inches of rainfall across Southern California's coastal and valley areas, with up to 12 inches likely in the foothills and in the Transverse Ranges. Rainfall rates are expected to be at least an inch an hour, with locally higher rates.

Strong winds, gusting upwards of 60 to 70 mph, could also cause downed trees and power outages, forecasters said.

The heavy rain will bring with it the threat of "life-threatening flash, urban, and river flooding," as well debris flows and mudslides, the NWS said. Dangerous high surf and coastal flooding is also likely along the coast.

Meanwhile, the combination of heavy snow in the mountains and strong winds could cause "dangerous, near impossible travel conditions." Several feet of snow are forecast for the Sierra Nevada Mountains through Tuesday.

Some 37 million Californians are at risk due to flooding, according to Dan DePodwin, AccuWeather's senior director of forecasting operations.

"Due to the numerous mountains and hills, even just a few inches of rain can cause significant flooding," DePodwin said. "The greatest risk of a widespread flooding disaster is expected across the canyons and hills of Southern California, especially in Ventura, Santa Barbara and Los Angeles counties."

Evacuation warnings have been issued for parts of Ventura, Santa Barbara and Los Angeles counties.

Californians have been urged to heed weather warnings, change travel plans to avoid flooded or dangerous roads, place sandbags in vulnerable areas of their property and prepare for any evacuation orders.

The NWS office in Los Angeles has placed much of Santa Barbara and Ventura counties at a "high risk" for excessive rainfall.

The office wrote on X, formerly Twitter, that "80% of flood-related DAMAGES and 40% of flood related FATALITIES occur during high-risk days."

Newsweek has contacted the National Weather Service for comment via email.

California was battered by a number of deadly storms last winter that caused extensive flooding. Thousands of homes were left without power and many were evacuated from their homes.