A major storm packing intense rain and heavy snow and winds will pound California and southern Oregon on Friday and through the weekend, forecasters said.
The National Weather Service said the system is expected to dump as much as 10 inches (25 cm) of rain at a rate of 1 inch (3 cm) per hour in parts of southern California on Friday.
"This looks to be the strongest storm to hit southwest California this season," the service said, adding that rainfall totals could be the highest in the area over the last six years.
The downpours in heavily populated counties of Santa Barbara, Ventura and Los Angeles where wildfires recently burned could create the risk of mud and debris flows, the weather service said.
"There will likely be widespread urban roadway flooding," it said. "There will also be a significant threat of rock and mudslides, especially near canyon roadways."
Rain was also forecast for northern California and southern Oregon, where the weather service issued a flood warning until Friday afternoon.
In areas of higher elevations in eastern California and western Nevada, as much as 2 feet (60 cm) of snow could cause whiteout conditions, forecasters said.
The area should also expect winds gusts of 75 mph (120 kph), potentially causing widespread power outages on Friday and Saturday, the service said.
(Reporting by Brendan O'Brien in Milwaukee; editing by John Stonestreet)