Officials are warning residents in Northern California to be ready to evacuate again as a second round of storms prepares to hit the Sunshine State. Torrential rain and flooding from the first round left at least seven people dead.

Another potent storm tapping an atmospheric river of moisture will hammer northern California Sunday night through early Tuesday, according to weather.com meteorologist Chris Dolce. Flooding and landslides are likely to occur in the storm-weary region with saturated ground conditions in place and gusty winds could topple some trees. Feet of snow will also pile up in the Sierra Nevada.

Colusa County Assistant Sheriff Jim Saso said Sunday that floodwaters are receding in the farm community of Maxwell, where dozens of people sought higher ground during flooding rain.

"We're telling these people to keep a bag close by and get ready to leave again," Saso told the Associated Press. "If the water comes back up, it's going to be those areas affected."

Nobody was hurt as crews used boats to rescue people from a low-lying residential neighborhood.

Authorities say the San Joaquin River is reaching flood stage and warning residents in Manteca to be ready to evacuate.

Saturday rescuers located the body of a man in his 20s who was swept away Friday afternoon in Ventura County, CBS Los Angeles reports. The man's body was found in the Aroyo Conejo Creek. His identity has not been released.

Two people were killed in a pair of fatal accidents on Interstate 15 Friday evening as more than 10 inches of rain fell in some parts of the region.

A car hydroplaned across Interstate 15 north near Mira Mesa Boulevard, striking multiple vehicles. One person died and three were injured , according to the California Highway Patrol.

In a separate two-car wreck on the rain-slicked Interstate 15 north of Interstate 805 , another individual was killed, according to NBC San Diego.

Multiple vehicles were swept away Friday night from a road in San Bernardino County, prompting the helicopter rescued of one person from the roof of a car, according to the Associated Press, while a rescue group was able to reach another submerged vehicle at Doris Davies Park in Victorville, where one individual was found dead , according to the San Bernardino County Fire Department.

A falling pine tree downed power lines, hitting a car in Sherman Oaks on Friday around noon. A 55-year-old man was electrocuted shortly after when he stepped in a puddle of charged water. He was transported to the hospital where he was pronounced dead on arrival.

A sinkhole opened up Friday evening near Studio City, California, swallowing two cars. One person was injured in the incident.

A second sinkhole opened on southbound Interstate 15, catching a fire truck on its edge. The truck eventually fell into the sinkhole. No injuries reported.

(PHOTOS: California Deluge )

Winds gusting to 70 mph or more lashed parts of the region, while heavy rains turned creeks and rivers into brown torrents, releasing slews of mud from hillsides burned barren by wildfires, reports the AP.

"At one point the wind was so strong I'm surprised it didn't blow my windows out," retiree Phoenix Hocking said from Carpinteria. "I now have a pond in my patio. And my dog is starting to grow flippers so he can go out and do his business."

In L.A.'s Sun Valley, 15 people had to be rescued when 10 cars were stuck in swift-moving water, according to AP. Seven people and two dogs were rescued from the Sepulveda basin along the Los Angeles River by firefighters with inflatable boats and ropes.

Four people were injured in Salinas' Chinatown Friday afternoon after strong winds brought down a tree , KION-TV reported. The extent of those injuries was not immediately known. In Los Angeles, 16 college students were evacuated from an apartment complex near UCLA after a large tree fell on the building. No one was injured in the incident, according to The Los Angeles Times.

In Duarte, where 180 homes were evacuated Friday near burn scars, mud flowed freely down hillsides and into streets, overflowing barriers that were put up to protect the homes. For the most part, homes had been spared serious damage as of late Friday evening, reports ABC 7. The evacuation was lifted on Saturday.

Mudslides became a major concern Friday afternoon, and along U.S. Route 101, one such slide closed the northbound lanes of the mud-covered freeway north of Ventura , according to the California Highway Patrol. Another mudslide closed Highway 154 at Painted Cave and Gibraltar.

A 20-mile stretch of State Route 138 in the West Cajon Valley was closed, according to the AP. Around two dozen vehicles, including tractor-trailers and a school bus, were soiled by mud or unable to turn around. Some vehicles were abandoned.

(MORE: Los Angeles Could See Most Rain in Years )

Voluntary evacuation orders were issued for parts of Camarillo Springs , according to the Ventura County Sheriff's Office of Emergency Services. The Santa Barbara Sheriff's Department issued an evacuation warning for the greater Sherpa fire burn area . The County Office of Emergency Management issued also issued an evacuation warning for parts of Solvang west of Santa Barbara.

Throughout Southern California, more than 28,000 customers remained without power as of 7:15 a.m. local time Saturday, according to SCE.

"It's crazy," Robin Johnson, an academic adviser at the University of California, Santa Barbara, told the AP. "It's just pouring down rain. The wind is just going nuts."

Powerful winds brought down trees crushed cars at Morro Bay High School and forced rangers to evacuate campers at Morro Bay State Park. Students were put on lockdown at the high school after several trees fell on campus, crushing two cars and the school’s solar panels.

(MORE: Latest On Oroville Dam Crisis )

Northern California

The California Department of Water Resources says the level of Lake Oroville continues to fall despite the stormy weather, and the amount of water flowing down the spillway continues to be cut.

The department says the amount of water flowing down the spillway has been reduced to 55,000 cubic feet per second. Earlier this week, outflows were at nearly 100,000 cubic feet per second. Work continues around the clock to shore up areas eroded below the spillway despite the weather.

Damage to spillways of the Lake Oroville dam forced the evacuation of 188,000 people last weekend.

Flooding was reported in Maxwell, prompting a voluntary evacuation notice Saturday afternoon, according to the National Weather Service. There are also reports of at least a foot of water on I-5 near the northern California town.

More than 70,000 customers were without power Friday across three counties near Santa Cruz after high winds knocked down two transmission power poles, according to KSBW-TV. Schools were closed Friday morning in Monterey and San Bernadino counties, the station also said.

Flooding is a concern in many of the reservoirs in central and northern California. Officials closely monitored the Anderson Reservoir, which is at 99 percent capacity , KGO-TV reported. The reservoir should only be at 68 percent because of seismic concerns, the station noted.