Rain and snow pummel Northern California in latest wave of damaging weather to strike West Coast

Rain and snow are pummeling Northern California as the region feels the effects of a major storm that could cause flash flooding and rockslides

SANTA ROSA, Calif. (AP) — A major storm pummeled Northern California with rain and snow on Wednesday night and threatened to cause flash flooding and rockslides in the latest wave of damaging weather to wash over the West Coast.

The National Weather Service extended a flood watch into Saturday for areas north of San Francisco as the strongest atmospheric river — a large plume of moisture flowing onshore — that California and the Pacific Northwest has seen this season inundated the region. The storm system unleashed winds the night before that left two people dead and hundreds of thousands without power in Washington state.

Up to 16 inches of rain (about 41 centimeters) was forecast in Northern California and southwestern Oregon through Friday. By Wednesday evening, some areas in Northern California had experienced heavy rain, including Santa Rosa, which had seen about 5 inches (about 13 centimeters) within 24 hours, according to Marc Chenard, a meteorologist with the National Weather Service.

Dangerous flash flooding, rockslides and debris flows were possible, officials warned. About a dozen small landslides had struck in northern California in the last 24 hours, including one on Highway 281 on Wednesday morning that caused a vehicle crash, said Chenard.

The National Weather Service in the Bay Area warned people that the atmospheric river was focused on the North Bay and to “expect heavy rain to continue tonight, Thursday into Friday. This will result in mudslides, road closures.”

The storm system, which first hit Tuesday, is considered a " bomb cyclone," which occurs when a cyclone intensifies rapidly.

A winter storm watch was in place for the northern Sierra Nevada above 3,500 feet (1,066 meters), where 15 inches (38 centimeters) of snow was possible over two days. Wind gusts could top 75 mph (121 kph) in mountain areas, forecasters said.

The storm had already dumped more than a foot of snow along the Cascades by Wednesday evening, according to the National Weather Service. Forecasters warned of blizzard and whiteout conditions and near impossible travel at pass level.

In Washington, there were nearly 376,000 power outage reports Wednesday evening, resulting from strong winds and rain the night before, according to poweroutage.us. Falling trees struck homes and littered roads across western Washington, killing at least two people. One 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 were closed in the Seattle area Wednesday and some opted to extend those closures through Thursday.

In California, there were reports of nearly 21,000 power outages as of Wednesday evening.

Southbound Interstate 5 was closed for an 11-mile (18-kilometer) stretch from Ashland, Oregon, to the California border on 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 were canceled at the San Francisco International Airport, according to Flight Aware.

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

___

Golden reported from Seattle.

A truck crosses a flooded road Wednesday, Nov. 20, 2024, in Santa Rosa, Calif. (AP Photo/Noah Berger)

Credit: AP

icon to expand image

Credit: AP

Firefighters help a woman from a home after a tree toppled onto it during heavy rains on Wednesday, Nov. 20, 2024, in the Forest Hills community of unincorporated Sonoma County, Calif. (AP Photo/Noah Berger)

Credit: AP

icon to expand image

Credit: AP

A Pacific Gas & Electric worker pauses while sawing a tree that toppled into power lines during heavy rains on Wednesday, Nov. 20, 2024, in the Occidental community of unincorporated Sonoma County, Calif. (AP Photo/Noah Berger)

Credit: AP

icon to expand image

Credit: AP

Truck driver Harry Singh of Seattle looks down Shastina Drive where several dozen big rigs were gathered after being stuck overnight in Weed, Calif., Wednesday, Nov. 20, 2024. (Carlos Avila Gonzalez/San Francisco Chronicle via AP)

Credit: AP

icon to expand image

Credit: AP

Truck driver Kirill Foken shovels a trench alongside his truck's tires to free it up as he awaits for I-5 to reopen in Weed, Calif., Wednesday, Nov. 20, 2024. (Carlos Avila Gonzalez/San Francisco Chronicle via AP)

Credit: AP

icon to expand image

Credit: AP

Truckers hole up along the side of I-5 to let the storm pass before the highway is reopened in Weed, Calif., Wednesday, Nov. 20, 2024. (Carlos Avila Gonzalez/San Francisco Chronicle via AP)

Credit: AP

icon to expand image

Credit: AP

Motorists negotiate the snow along I-80 during a storm Wednesday, Nov. 20, 2024, in Truckee, Calif. (AP Photo/Brooke Hess-Homeier)

Credit: AP

icon to expand image

Credit: AP

A pedestrian carrying an umbrella walks in front of the Golden Gate Bridge in San Francisco, Wednesday, Nov. 20, 2024. (AP Photo/Jeff Chiu)

Credit: AP

icon to expand image

Credit: AP

People carrying umbrellas while visiting the Golden Gate Bridge are seen through a heart on the window at the Round House Cafe in San Francisco, Wednesday, Nov. 20, 2024. (AP Photo/Jeff Chiu)

Credit: AP

icon to expand image

Credit: AP

People walk their dog as cars maneuver around downed power lines and trees caused by a "bomb cyclone" storm, Wednesday, Nov. 20, 2024, in Bellevue, Wash. (Nick Wagne/The Seattle Times via AP)

Credit: AP

icon to expand image

Credit: AP

A woman was killed after a tree fell on her home during Tuesday night's "bomb cyclone" in severe weather in Bellevue, Wash. (Nick Wagner/The Seattle Times via AP)

Credit: AP

icon to expand image

Credit: AP

The drive-thru area of a Taco Bell restaurant is damaged by a fallen tree Wednesday, Nov. 20, 2024, in Issaquah, Wash., after a "bomb cyclone'"storm brought high winds to the area. (AP Photo/Manuel Valdes)

Credit: AP

icon to expand image

Credit: AP