SAN FRANCISCO — More than 1,000 homes were evacuated in northern Nevada, and stranded motorists were pulled from cars stuck on flooded Northern California roads as thunderstorms arrived Sunday as part of a massive winter storm that could be the biggest to slam the region in more than a decade.

Crews in California cleared trees and debris after mudslides caused by steady rain accompanying the system that could dump 15 inches in the foothills of the Sierra and heavy snow on the mountaintops before it’s expected to move east Monday.

In Nevada, emergency officials evacuated 1,300 homes in a south Reno neighborhood Sunday afternoon as the Truckee River began to leave its banks and drainage ditches started to overflow south of Interstate 80.

No injuries had been reported, but high waters forced the closure of numerous roads, a series of bridges in downtown Reno and a pair of Interstate 80 off-ramps in neighboring Sparks, where the worst flooding was expected to send several feet of water early Monday into an industrial area where 25,000 people work.

An avalanche also closed a portion of the Mount Rose Highway connecting Reno to Lake Tahoe for the second time in three days after more than 6 feet of snow fell atop the Sierra last week.

Authorities say they expect Reno-Tahoe International Airport to remain open. But schools were ordered closed Monday throughout the Reno-Sparks area, and Gov. Brian Sandoval told all non-essential state employees to stay home.

Bob Leighton, the Reno Fire Department’s chief of emergency operations, called it “a very dynamic situation that’s happening so fast it’s hard to keep up with the road closures.”

The storm surge stretching all the way from Hawaii comes as California enters its sixth year of drought. Each drop of rain is welcomed, but officials said several more big storms are needed to replenish depleted groundwater supplies.