Californians were urged to flee ahead of flooding in Sacramento County, where the state capital is located, while northern California was also experiencing blizzard conditions that have shut down travel near the Nevada border.
Sacramento County was bracing for the Cosumnes River levee to possibly overflow its banks on Wednesday, reported USA Today.
Blizzard conditions shut down Interstate 80, cutting off the town of Truckee near the Nevada border, reported CBS News. Blizzard conditions have also shut down a major highway connecting Reno to Lake Tahoe.
About 2,000 people in the Wilton community were asked to evacuate by the Sacramento County Sheriff's Department Tuesday as the American Red Cross opened up two evacuation centers in the areas, noted the newspaper.
Mary Jo Flynn, a Sacramento County emergency services official, told USA Today that water was expected to start spill over the levee, flooding low-lying roads and buildings with up to a foot of water.
KXTV said the Cosumnes River was the only river in the western Sierra without major dam control.
"The water is crazy powerful," said Tim Chappell, who manages the Kautz Vineyard in Wilton. "Looking at it, watching it. But the sound of it, especially when it breaks...it's got a really hurting sound to it."
Chappell, who has been with the vineyard for four decades, said many still remember the 1997 flood that seriously damaged area businesses.
"We've been monitoring the river since 9 [Sunday] night," Chappell told the television station. "Literally, you could not see the vines (in 1997). It just looked like an ocean. At this time, we're fine. Another foot and you know we'll be in more danger."
CBS News said the Russian River in Guerneville was expected to crest Wednesday, eight feet above flood level. About 3,000 people in Sonoma County are under evacuation orders there.
"Our biggest concern is possible trees coming down, power outages," John Gulserian of the Nevada County Office of Emergency Services.