Storms have soaked the San Francisco Bay Area, dumping fresh snow in the Sierra Nevada and bringing a high tide that flooded some coastal areas.
Heavy rainfall was expected to cause two rivers in the Northern Coast to reach flood level late Sunday, the Humboldt County Sheriff's office said.
The area was expected to receive up to 2.5 inches of rainfall before the storm spreads further inland, said Roger Gass, a forecaster with the National Weather Service.
The Sierra Nevada was forecast to get up to 10 inches of new snow in the highest points, Gass said. Vehicles were required to travel with chains along the higher elevations of Interstate 80 due to hazardous conditions.
A flood advisory for roadways and small streams was issued Sunday in Sonoma and Marin counties, the weather service said. Around two to three inches of rain fell in recently burned areas in nearby Lake County, including the destructive Valley Fire that killed 4 and destroyed more than 1,000 homes.
A second rainstorm is expected to make landfall Monday night and Tuesday, Gass said, adding, "There will be a few lingering showers across the region Monday morning but most conditions will become dry by the afternoon."
As El Niño-fuled storms drenched the Bay Area over the weekend, residents of Napa, San Anselmo and Mill Valley picked up plastic and sandbags to protect their properties
But the rain, coming down in sheets Sunday, created problems for many residents, including flooded roads and downed trees. Nearly 500 people also were temporarily without power in Oakland and Piedmont because of downed wires, according to PG&E.
Waves – some of which were up to 18 feet high and crashed over a retaining wall – washed away a section of wall and a walkway on Beach Boulevard in Pacifica.
Crews spent the day building a makeshift wall with huge boulder to block the hole and protect nearby houses.
Mia Carley who lives just a few feet away from the damage said waves hurled and rocks at her house.
"The waves were crashing at my window," the Pacifica resident said. "It sounded like an earthquake."
Carley’s family is relying on boards and sandbags to defend their home against the intruding water and sand.
The pounding surf also caused some damage to the Pacifica pier, forcing it to close for the day. But that didn’t keep the curious away.
"I was surprised to see the storm had brought the sand right up to the houses," said Armando Laguna of Sunnyvale. "I had never seen an aftermath like that."
To that, Dolores Rodriguez of San Bruno added: "I love the water, I love the waves but if they get any higher than this, I'll be out of here."
The storms were accompanied by a large ocean swell bringing 15- to 20-foot-tall waves along the central and southern California coast. The weather service warned of minor beach erosion and minor flooding in low-lying coastal areas during high tide.
NBC Bay Area's Rhea Mahbubani contributed to this report.