Heavy Rain, Floods Drench California as Thousands Urged to Evacuate

A powerful band of thunderstorms over California this week has swollen rivers, downed trees and prompted many people to evacuate, with more days of heavy rain in the forecast.

Authorities urged thousands of residents in Northern California to evacuate as pounding rain threatened to overflow rivers. About 2,000 people in Wilton, a rural community near Sacramento, were asked to leave their homes Tuesday night, according to The Associated Press.

Meanwhile, some 3,000 residents in Sonoma County were under an evacuation advisory as the Russian River crested Monday at 35 feet, flooding several low-lying neighborhoods, according to ABC's San Francisco station KGO.

ABC News meteorologists say the Russian River will continue to rise Wednesday and will approach 39.8 feet in the evening at Guerneville, the largest town along the river.

ABC News meteorologists are monitoring other rivers for flooding. The Napa River was causing moderate inundation Wednesday morning but is expected to begin receding in the afternoon. Rain sent the Navarro River significantly over the flood stage Wednesday morning, but it will recede by the afternoon, ABC News meteorologists said.

Multiple school districts in Northern California were closed Wednesday because of the weather, according to ABC affiliate KXTV. Dozens of states, from California to New Jersey, were under winter weather alerts as of Wednesday morning.

In the past seven days, Central California has received over 2 feet of rain, causing rivers to overflow and flood roads, cities and many of the Golden State's famed vineyards, according to ABC News meteorologists

While rain drenches the state's lower-lying areas, snow is blasting elevated regions. The Mammoth Mountain ski resort in the eastern Sierra Nevada reported 15 feet of new snow in six days.

"The resort is approaching their all-time snowiest January on record," ABC News senior meteorologist Max Golembo said.

A small tornado touched down near Sacramento early Wednesday morning, according to the National Weather Service. The twister ripped limbs off trees and awnings from buildings, but no injuries were reported.

"This is the time of the year when California would see them - in the winter," Golembo said of tornadoes, adding that the twister was at the bottom of the tornado scale, an EF-0.

The storm is forecast to move out of Central California on Wednesday and bring snow to the Rocky Mountains and rain to the Los Angeles area in Southern California, which is entering its sixth year of severe drought.

Meanwhile, a new weather system is moving in from the west and will dump even more rain beginning late Wednesday into early Thursday. The storm will approach Northern California by Wednesday night before moving into Central California.

ABC News meteorologists predict the new system will produce locally over 2 inches of rain in California through Friday.