More than 9,000 California residents were under evacuation orders Friday as a new atmospheric river brought heavy rain, thunderstorms and strong winds, swelling rivers and creeks and flooding several major highways during the morning commute.
Some rivers are out of their banks already:
Widespread heavy to excessive rainfall will continue through the day on Friday over an area already soaked by a prolonged wet period and by recent rainfall from a passage of several waves.
Evacuation warnings have been issued because of flooding threats from what is called the "Pineapple Express," due to moisture streaming into the state from the tropical Pacific. The atmospheric river will extend for more than 2,400 miles from California to the southwest of Hawaii.
California Governor Gavin Newsom has declared a state of emergency in 21 counties. The governor has also asked for a presidential emergency declaration to help with the state's emergency storm response.
Some flooding is already taking place in Tulare County, Cal.
About midnight, residents in a part of Santa Cruz County south of San Francisco were advised to evacuate, when the San Lorenzo river began to flood. In a message from the county of Santa Cruz, "Felton Grove, Paradise Park and Soquel Village are being evacuated. Please move to higher ground."
Just to the north in San Mateo county, falling trees are a concern. A Tesla was crushed by one such tree.
Some roads closed Thursday because of flooding while downed trees and mudslides blocked others.
Snowmelt in the Sierra Nevada could lead to ponding of water and rises to creeks, streams, and rivers. The National Weather Service says as snow levels rise into the 8000-10000 foot range, rainfall on snowpack will likely result in areas of increased runoff and rapid onset of flooding. The equivalent of 8-12 inches of water could be released in a only a few hours due to the snowmelt and already saturated ground.
At higher elevations in the Sierra, 2-4 feet of new snow is expected. Roadways like Interstate 80 and Highway 50 should be impacted, with closures possible.
Another atmospheric river is expected to move through the area next week, compounding the flooding issue.