LOS ANGELES (REUTERS) - The worst of the rain, snow, and winds carried by the so-called Pineapple Express, a river of warm air loaded with moisture, will hit California on Thursday (Feb 14) and stick around at least through Friday, forecasters said.
The weather system, headed east from near Hawaii, is the wettest storm on the US West Coast this season.
It has swamped cars, flooded vineyards and forced hundreds of Californians to evacuate their homes on Wednesday to escape the threat of mudslides.
Five people suffered minor injuries when turbulence shook a Delta Air Lines flight headed from southern California to Seattle on Wednesday, multiple media accounts said.
The plane, a Embraer 175 aircraft operated by Compass Airlines under contract with Delta, was forced to land in Reno, Nevada, at about 1pm on Wednesday, according to the Reno Gazette Journal and other media.
"We did a nose dive twice," a passenger wrote on Twitter, according to the newspaper.
"That whole area from Southern California and on up to Washington is primed for severe turbulence at altitude, especially over the mountains" said Mr David Roth, a forecaster with the National Weather Service's Weather Prediction Centre in College Park, Maryland.
Delta did not immediately respond to inquiries from Reuters early on Thursday.
Mr Roth said risks for motorists will be highest during Thursday's morning commute.
Some mountain areas in southern and central California will get up to an inch (2.54cm) of rain an hour for at least three hours, with the rain continuing throughout the day.
"It will be the most dangerous in areas where there were wildfires," he said. "The ground is already saturated with water and there's not much vegetation left to hold the soil."
Some areas around Los Angeles could see over 13cm of rain from the storm, which is being channelled to the coast by the flow of atmospheric moisture.
Residents of Lake Elsinore, 90km east of Los Angeles, got mandatory evacuation orders because nearby hillsides, scorched by fire in 2018, might turn into rivers of mud and debris that could carry away cars and homes.
Among the hardest-hit areas was northern California, where rain driven by winds up to 120km per hour pounding parts of Sonoma County's wine country.
Cars ploughed through standing water on San Francisco streets and water reached the wing mirrors of an abandoned car on a flooded Santa Cruz road.
The NWS also expects over 2.4 metres of snow in some areas of the Sierra Nevada mountains.
The Pineapple Express is one of a string of storms that have swelled snowfall in California to above-average levels, delighting farmers and skiers following years of drought.