After a series of unrelenting winter storms, California is forecast to see another slate of grueling weather, including heavy rain and snow to last through the weekend.
As heavy rains hit parts of the state on Friday, more than 9,000 residents were under evacuation orders, according to the Associated Press. The rain flooded major highways, roads, rivers and creeks, with several counties in the Bay Area operating under a National Weather Service flood warning in the morning through the early afternoon. Further west areas along the Sierra Nevada Mountains, like in South Lake Tahoe, got heavy, dangerous snowfall.
The severe weather is the result of back-to-back atmospheric rivers, the first of which arrived on Thursday. The second is expected to make landfall on Monday afternoon, according to Brian Ochs, a meteorologist for the National Weather Service based in Hanford, Calif.
The storm was expected to be warmer, creating a dangerous combination of excessive rain and snowmelt in some areas that could pose serious risk of flooding.
"Lately we've had snow levels as low as 1500 feet, but since we have warmer air, we're seeing snow in elevation as high as 7,000 feet and above," Ochs told NPR.
Earlier this week, California Gov. Gavin Newsom proclaimed a state of emergency in 21 counties. Newsom also has requested federal assistance in anticipation of the state's need to respond to the extreme storms. President Biden later approved this request on Friday.
What is an atmospheric river?
Also known as "rivers in the sky," these meteorological phenomena develop when a relatively long, narrow channel of wind transports water vapor from the tropics. The current atmospheric river pummeling California is called a "Pineapple Express," because the moisture arrived from the tropics near Hawaii.
The columns of highly concentrated moisture move with the weather, and when they make landfall, they can produce heavy rain or snow. Atmospheric rivers with the largest amounts of water vapor and strongest winds can lead to severe rainfall, causing mudslides and property damage.
The storm drops several inches of rain and washes out roads
By mid-afternoon, rain tapered off in the Bay Area, according to the National Weather Service.
That wasn't before the storm brought several inches of rainfall to the area and some reported damage. The NWS reported that King City, Calif., received more than 12 inches of rain over 48 hours.
A large section of a road in Soquel, a town in Santa Cruz County, was completely washed out by the storm, stranding residents. Mudslides closed roads elsewhere in the county, according to emergency responders. Crews worked to clear debris by late morning.
In Oakland, part of the roof of a Peet's Coffee distribution center collapsed, killing one worker and injuring another woman early Friday morning, according to the city's fire department. Investigators told a local television news station that they aren't ruling out the roof's collapse as being storm related.
Lake Tahoe faces threat of avalanche threat
Residents on the eastern part of the state around Lake Tahoe were under a serious weather warning due to heavy amounts of snowfall.
The Sierra Avalanche Center warned, "Widespread avalanche activity is expected to occur with heavy loading of the snowpack from rain and high intensity snowfall. Travel in, near, or below avalanche terrain is not recommended."
Caltrans District 3, which maintains the state highway system in Northern California counties, showed the extent of the massive amount of snow that fell on Highway 50 overnight during an avalanche control operation.
Here are some photos of the massive amount of snow that fell onto Highway 50 overnight during an avalanche control operation. The highway is open without chain controls this afternoon but please watch out for snow removal equipment. @CountyElDorado @CHPSouthLake @cityofslt pic.twitter.com/YRR8YMaubK
— Caltrans District 3 (@CaltransDist3) March 10, 2023
The Tahoe Daily Tribune reported that the roofs of at least two businesses in South Lake Tahoe collapsed due to snow load.
More storms are coming
The downpour is expected to lighten by Sunday in the central region, giving some respite, before a second atmospheric river brings heavy rain on Monday and Tuesday, with lingering showers on Wednesday, said Ochs from the National Weather Service.
In northern California, areas with higher elevation are expected to see heavy, wet snow. Meanwhile, creeks and streams in the foothills of the Sierra Nevada are forecast to be the most vulnerable to flooding from rain and snowmelt.
Southern California is expected to see minor flooding on roads and along small creeks. In Santa Barbara, there is a moderate threat of significant road and stream flooding, particularly in the northern part of the county.
