Rain and snow hit northern California; wave of bad weather persists on the west coast of the US

A group of people walk in front of a car on which a tree fell during a storm in Issaquah, Washington state, on November 20, 2024.

The US National Weather Service issued a flood warning for areas north of San Francisco, as the so-called atmospheric river flooded the California region and the Pacific Northwest. The storm system left two dead in Washington state.

A severe storm hit Northern California with rain and snow Wednesday night and threatened to cause flash flooding and rock slides, in the latest round of damaging weather to hit the U.S. West Coast.

The National Weather Service issued a flood warning through Saturday for areas north of San Francisco, as the strongest atmospheric river — a large current of moisture flowing toward the coast — that California and the Pacific Northwest have seen this season inundated the region.

The storm system produced winds last night that claimed two lives and left hundreds of thousands of people without power in Washington state.

Up to 16 inches of rain was expected in northern California and southwestern Oregon through Friday. By Wednesday night, some areas in Northern California had experienced heavy rain, including Santa Rosa, which had received about 5 inches in 24 hours, according to Marc Chenard, a meteorologist with the National Weather Service.

Warnings were given of the risk of dangerous flash floods, rock slides and torrents carrying debris. About a dozen small mudslides had occurred in Northern California in the past 24 hours, including one on Highway 281 early Wednesday that caused a traffic accident, Chenard said.

The National Weather Service delegation in the San Francisco Bay area warned the population that the atmospheric river was centered in the north of the region and to expect “heavy rain to continue tonight, Thursday and Friday.” “This will result in landslides, road closures.”

The storm system, which first hit on Tuesday, has experienced what is known as a “bomb cyclone,” a process in which a cyclone rapidly intensifies.

There was a winter storm warning for the northern Sierra Nevada above 1,066 meters, and 38 cm of snow could fall in two days. Wind gusts could exceed 121 kilometers per hour in mountainous areas, forecasters said.

The storm had already dumped more than a foot of snow across the Cascades area by Wednesday night, according to the National Weather Service. Forecasters warned of blizzard conditions and poor visibility due to snow and warned that it would be nearly impossible to cross mountain passes.

In Washington, there were nearly 376,000 reports of power outages Wednesday night, the result of high winds and rain the night before, according to poweroutage.us.

Fallen trees hit homes and blocked roads in western Washington, killing at least two people. A woman in Lynnwood was killed when a large tree fell on a homeless encampment, while another woman in Bellevue was killed when a tree fell on a home.

More than a dozen schools closed in the Seattle area on Wednesday, with some opting to extend those closures through Thursday.

In California, nearly 21,000 power outages were reported as of Wednesday night.

Southbound Interstate 5 was closed for a 11-mile stretch from Ashland, Oregon, to the California border Wednesday morning due to extreme winter weather conditions in Northern California, according to the Oregon Department of Transportation. It was expected to be a long-term closure, the department said.

Hundreds of flights were delayed and dozens canceled at San Francisco International Airport, according to Flight Aware.

The weather service issued a flood watch for parts of southwestern Oregon through Friday night, while winds and rough seas temporarily halted a ferry route in northwest Washington between Port Townsend and Coupeville.