Atmospheric river threatens historic life-threatening floods in California

California was slammed by a “life-threatening” atmospheric river on Sunday bringing dangerous rainfall, flash flooding, hurricane-force winds, possible tornadoes, and huge snowfalls.

The first hurricane force wind warning in history was issued by the National Weather Service (NWS) for the Bay Area in the early hours of Sunday.

Forecasters warned of wind gusts up to 90mph off Big Sur. Isolated thunderstorms and winds from San Jose to the Central Coast were expected throughout Sunday.

“Heavy rain and flooding are concerns today, especially for the Santa Cruz and Santa Lucia Mountains where several inches of rain are expected,” NWS Bay Area said on X, formerly Twitter, on Sunday morning.

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By Sunday afternoon, more than 200,000 customers were without power, according to utility tracker poweroutage.us.

NWS Los Angeles issued a stern warning that the “dangerous” storm held “major risks to life and property,” including “substantial flooding”.

“Residents should heed any evacuation orders. Stay off the roads, especially the freeways, this afternoon through at least Monday morning,” forecasters wrote.

Rockslides and mudslides were expected as months’ worth of rain were set to deluge parts of the state in a matter of days. Large areas of California are already saturated after a separate storm earlier this week.

NWS Oxnard said that Sunday would be “one of the most dramatic weather days in recent memory”.

Los Angeles could see up to 15 inches of rain through Wednesday. Further north, more than a foot of snow had already fallen in 24 hours in the Lake Tahoe mountain area.

Dr Daniel Swain, a climate scientist, said on Sunday that “this storm is cranking off the coast and behaving largely as expected”.

“There’s lots of folks saying, ‘why hasn’t the rain been heavier at my house? Why hasn’t the wind been stronger?’ In a lot of cases, that’s just because it hasn’t arrived yet at specific locations,” he said.

“Just to reiterate, a lot of folks are saying ‘oh it’s sunny and 70 degrees, partly cloudy in Southern California. This storm was a bust’. No, it’s still just 500 miles to your west,” Dr Swain added.

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“It is absolutely coming. If anything, it looks a little bit wetter even than it did yesterday. And those were already some pretty extreme totals.”

The storm is dubbed a “Pineapple Express” because the system drags moisture across the Pacific from Hawaii.

It had already began upending events in the Golden State. Both a NASCAR event and the PGA Golf tour were affected by the weather, and more than 100 flights had been cancelled at San Francisco International Airport on Sunday. Almost 300 flights were delayed, according to FlightAware.

Evacuation orders were issued in Ventura County, an area facing runoff from mountain areas which have seen a foot of rain. Orders to evacuate were also in effect for Santa Barbara, Los Angeles, and Monterey counties, the AP reported.

Large parts of the California coastline were under flood watches along with wind warnings.

“This storm is predicted to be one of the largest and most significant in our county’s history and our goal is to get through it without any fatalities or any serious injuries,” Sheriff Bill Brown of Santa Barbara County told the AP.

“Roughly 94 per cent of California’s population, up to 37 million people, is at risk for life-threatening flooding,” AccuWeather Senior Director of Forecasting Operations Dan DePodwin said ahead of the storm.