WATSONVILLE, Calif. (AP) — Wet, miserable weather continued across huge swaths of California on Sunday as an atmospheric river that caused major flooding flowed eastward, while a new storm threatened another onslaught of rain, snow and gusting winds as soon as Monday.

The National Weather Service said the next system could exacerbate severe flooding that overwhelmed the area in recent days, prompting a levee failure and widespread evacuations Saturday in farming communities near the state’s central coast.

The new storm is not expected to bring as much rain, but forecasters warned that “considerable flooding” could occur at lower elevations from additional rain and creeks and streams swollen with snowmelt.

“Definitely prepare for some more flooding impacts. The ground is very saturated. We’re already seeing some impacts from some light amounts,” National Weather Service forecaster Eleanor Dhuyvetter said.

A tornado briefly touched down in Tuolumne County during severe thunderstorms Saturday that also dumped an inch (2.5 centimeters) of hail, the weather service office in Sacramento said. Tornadoes were possible again Sunday afternoon, forecasters warned.

Monday’s incoming rain and snow is expected to extend from central California to Oregon and northern Nevada. Wind gusts of up to 50 mph (80 kph) are expected in some places and could damage power lines and snap tree branches.

But the new storm is moving fast, meaning it won’t have time to dump as much rain.

Over the past two days, more than 20 inches (50 centimeters) of snow fell at a measuring station in the Sierra Nevada, and more is expected. The snowpack is now nearly twice the average, and the highest in about four decades, according to UC Berkeley’s Central Sierra Snow Lab.

The snowpack stores much-needed water for a state seeking to emerge from a three-year drought.

As much as a foot (30 centimeters) of rain fell in the Big Sur area of the state over a two-day period, weather data.

Authorities suggest that residents have a plan in case further evacuations orders are issued.

Across Monterey County, more than 8,500 people were evacuated Saturday, including roughly 1,700 residents — many of them Latino farmworkers — from the unincorporated community of Pajaro.

“We are still in disaster response mode,” said Monterey County spokesman Nicholas Pasculli on Sunday. He said the county is staging high water rescue teams around the county and opening more shelters in anticipation of more flooding.

Highway 1, also known as the Pacific Coast Highway, is closed at several points along Big Sur as well as near Pajaro due to flooding.

The atmospheric river, known as a “Pineapple Express” because it brought warm subtropical moisture across the Pacific from near Hawaii, was melting lower parts of the huge snowpack in California’s mountains.

Because of the massive flooding over the early weekend, more than 50 people had to be rescued by first responders and the California National Guard. One video showed a Guard member helping a driver out of a car trapped by water up to their waists.

The extent of property damages was still uncertain but Luis Alejo, chair of the Monterey County Board of Supervisors, sought help from the state and federal governments.

“The need will be great! Will take months for our residents to repair homes!” he wrote in a tweet Saturday.

Gov. Gavin Newsom has declared emergencies in 34 counties in recent weeks, and the Biden administration approved a presidential disaster declaration for some on Friday morning. President Joe Biden spoke with Newsom on Saturday to pledge federal support for California’s emergency response, the White House said.

Weather-related power outages affected more than 17,000 customers in Monterey County late Saturday, according to the Governor’s Office of Emergency Services. By late Sunday morning, about 7,000 were still without electricity.

The governor’s office said it was continuing to monitor the situation in Pajaro.

The Pajaro River separates the counties of Santa Cruz and Monterey. Officials had been working to shore up parts of the river’s levee system when it was breached around midnight Friday into Saturday. Crews began working to fix the levee around daybreak Saturday as residents slept in evacuation centers.

Built in the late 40s to provide flood protection, the levee has been a known risk for decades with several breaches in the 1990s. Emergency repairs to a section of the berm was undertaken in January. A $400 million rebuild is set to begin in 2025.

This week’s storm marked the state’s 10th atmospheric river of the winter, storms that have brought enormous amounts of rain and snow to the state and helped lessen drought conditions. State reservoirs that had dipped to strikingly low levels are now well above the average for this time of year, prompting state officials to release water from dams to assist with flood control and make room for even more rain.

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Dazio reported from Los Angeles. Associated Press writers Martha Mendoza in Santa Cruz, California, and Bobby Caina Calvan in New York contributed.