Sacramento County warns residents amid storms: 'Get out now'

There is no end in sight for the unrelenting rainfall inundating the West Coast with severe flooding and widespread power outages.

Residents in Wilton, California, who live along the Cosumnes River, are being urged to evacuate immediately amid the storm in anticipation of the river flooding over.

"We are urging residents to get out now while roads are still clear; don't wait for an evacuation order," the Sacramento County Office of Emergency Services told residents in its announcement on Sunday.

"Rising water may soon spill over onto roads in Wilton and cut off evacuation routes. More rain & wind in the 50-60 mph range is forecast for Sunday night into Monday," Sacramento County tweeted later Sunday.

This same area was slammed by last weekend's atmospheric river, which led to multiple levee failures along the Cosumnes and inundated much of the area with flooding.

That flooding prompted a shelter-in-place order in Wilton after flood waters cut off routes for residents to evacuate, and three people died in the weather event. They were found in their vehicles.

Gov. Gavin Newsom on Sunday warned Californians that intense weather is coming in, and officials anticipate that the worst of the storms is yet to come. The state is preparing and has activated emergency response teams and staged equipment throughout the state, Newsom said. The governor's office later said it has submitted a request to the White House for a presidential emergency declaration.

Nearly 500,000 customers across California were without power on Sunday morning as the state continues to be walloped by an ongoing atmospheric river.

The ground that is typically parched as a result of a decadeslong megadrought has now been overly saturated with moisture that threatens to continue for several days. Some coastal roads have been washed away and homes flooded, and heavy rain and mountain snow continued into Sunday morning.

Northern California will see about a 12-hour break from 9 a.m. to 9 p.m. local time on Sunday, with another round of heavy rain and snow to follow Sunday overnight into Monday morning. The region will be afforded with another break from about 7 a.m. Monday to midnight on Tuesday, forecasts show.

Further south, the "fire house" of rain is expected to move down the state, with heavy flooding rains expected to hit the area between San Francisco and Los Angeles with non-stop rain from Sunday evening to Monday evening.

There is no light at the end of the tunnel for Californians hoping to see a break in the rain. The pattern is expected to continue in the coming week and into the next week wave after wave of atmospheric moisture affecting the coast.

Rain totals through Tuesday in northern California and the central coast are expected to be 2 inches to 5 inches in the valleys, up to 7 inches in the hills and between 6 inches and 12 inches in the mountains, forecasts show.

The influx of moisture will likely create more mudslides, debris flows -- especially in the burn scar areas -- and rapid rises of creeks, streams and rivers.

The San Lorenzo River near Santa Cruz, a coastal town about 90 miles south of San Francisco, is forecast to reach a major flood stage on Monday, nearing 23 feet. At about 21.76 feet, major flooding occurs in the Felton Grove neighborhood, with roadways several feet deep and waters inundating the approaches to the Felton Covered Bridge, according to the National Weather Service.

The Alameda Creek near Niles, about 30 miles southeast, of San Francisco, is forecast to reach near record at 15 feet on Monday. The Alameda Creek in general will be near a record height, not just at this location.

Winds with gusts up to 70 mph will continue to bring down trees and power lines, causing power outages and an unrelenting danger for people and homes within a short distance of trees.

Up to three feet of snow will have fallen in the Sierra Nevada by the time the weekend is over. Another 4 feet is possible in some regions through Tuesday alone, with more to come as the week progresses.

The moisture is also making its way further east, with western Colorado reporting 13 inches of snow over the weekend.

ABC News' Nicholas Kerr and Marilyn Heck contributed to this report.