A canal levee broke near Reno, Nevada, flooding an estimated 800 homes and causing at least 3,500 residents to evacuate by helicopter and boat, a department of public safety spokesman said.
Ted Kulongoski, the governor of Oregon, declared a state of emergency in Umatilla county, in the northeastern corner of that state, due to high winds that ravaged the area.
"[The bad weather] will continue through at least tomorrow, and then there's another round on Monday," Jane Hollingsworth, a spokeswoman for the US national weather service, said.
The weather affected Los Angeles and communities to the south in Orange County, where roughly 3,000 people had been asked to leave their homes in hillside areas hit by wildfires and prone to mudslides.
But no major slides occurred and no significant damage was reported to homes or buildings.
There were relatively few power outages in southern California, and by Saturday most electricity had been restored to residents.
However, in northern and central California up to 1.8 million people are without electricity.