U.S. Highway 101, one of California’s most famous highways, was closed in both directions south of San Francisco on Saturday as heavy rain and snowmelt flooded the road, especially in the northern half of the state.
The California Department of Transportation also recommended a partial closure of Interstate 80 near the Nevada state line at noon Saturday, “due to the multiple break-ups at Donner Summit.” Driving through the Sierra Nevada mountain pass for much of the month will require Tire chains.
A powerful storm began delivering widespread torrential rain Friday through Saturday, threatening flooding across much of northern and central California. The active jet stream pattern also continued to bring storm marches fueled by atmospheric rivers of moisture in the Pacific Ocean.
An atmospheric river is a long, narrow region of the atmosphere that can transport moisture thousands of miles, like a fire hose in the sky. The heavy rain will slide south toward Southern California on Saturday and Sunday with gusts of 30 to 50 mph.
Several small communities in northern California received evacuation orders and warnings Saturday due to flooding. Three communities near Watsonville were told to evacuate by the Santa Cruz County Sheriff’s Office because of flooded streams, while officials ordered the communities of Paradise Park and Felton to evacuate due to rising water levels in the San Lorenzo River.
Communities near Santa Rita Creek in Monterey County were warned Saturday afternoon over concerns the creek “would overflow its banks,” according to the sheriff’s office.
Flood warnings were in effect for more than 16 million people as of Saturday night, including for the entire Bay Area and Central Valley. Saturday night’s rain could ease before the calendar turns to 2023.
Earlier forecasts said widespread rain of 2 to 4 inches was expected for northern and central California, but localized rain of 5 to 7 inches was also possible in the foothills.
The Northern and Central California coasts have seen 2 to 4 inches of rain last week. The cumulative effect of multiple Pacific storm systems filled with moisture from powerful atmospheric rivers will make impacts such as flash floods and landslides more likely.
Videos and Photos The weather shared by the National Weather Service in San Francisco showed fallen trees blocking roads and multiple landslides.
“Rain gauges in downtown San Francisco are now reporting 5.33 inches today,” San Francisco Office of the National Weather Service Say. “Running for the wettest calendar day ever recorded… (records go back to 1849).”