SAN FRANCISCO – A strong atmospheric river is flooding much of the West Coast with heavy rain and potentially damaging wind gusts, leaving over 150,000 people without power Saturday morning.

The San Francisco Bay Area faced multiple threats Saturday morning, including a brief tornado warning. Flood watches covered the North Bay into Northern California, with rainfall expected at 2 to 3 inches in the valleys, increasing to 5 inches in higher elevations.

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Just before 6 a.m. Saturday morning, a tornado warning was issued for over 1 million people in the heart of downtown San Francisco after Doppler radar showed a rotation as a strong thunderstorm raged across the city.

The danger passed about 20 minutes later with no reports of landings or damage, but the storm brought 83 mph gusts to San Francisco International Airport.

According to the National Weather Service, Saturday’s tornado warning was believed to be the first ever issued for the city of San Francisco.

A street floods in Livermore, California on December 14, 2024.

(Livermore Police Dept./FOX Weather)

NOAA’s Storm Prediction Center had placed the Bay Area in a Level 1 out of 5 severe weather threat by Saturday morning due to the potential for severe thunderstorms that could bring large hail, damaging wind gusts over 55 mph – and still that Risk of a single tornado.

The Weather Prediction Center also puts the Bay Area at a level 2 out of 4 flash flood risk. A flood warning covers the heart of downtown San Francisco for potentially flooded streets and subways.

Further east, heavy snow is expected in the Sierra Nevada and winter storm warnings are in effect. Up to 8-20 inches is expected at higher elevations. Wind gusts could reach speeds of 120 mph along the mountain ridges and over 72 mph in the valleys.

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The weather will improve across the Bay Area and Northern California later Saturday as the storm moves inland.

Strong winds and coastal flooding rock western Washington

For the Pacific Northwest, the storm posed a serious threat of coastal flooding due to a mix of heavy rainfall and strong winds.

Along the Washington coast, gusts reached 62 mph early Saturday morning in Forks and 61 mph in Hoquiam, where high wind warnings were in effect.

A dangerous combination of pounding surf of 20 to 23 feet, extreme spring tides and low barometric pressure threatened significant storm surge and coastal flooding.

NWS Seattle warned of flooding that could reach depths of 2.5 to 3.5 feet along the coasts and in low-lying areas during high tide late Saturday morning.

“This is expected to result in numerous road closures,” NWS Seattle warned. “Priority property, including homes, businesses and some critical infrastructure, may be flooded. There may be coastal erosion or damage.”

Another atmospheric river – the third this week – flows to the West Coast early next week but is expected to be weaker than Saturday.