Nurse Katie Leonard, left, hands a cup of hot tea to Patsy Costello, 88, as she sits trapped in her vehicle for over an hour on Astrid Drive in Pleasant Hill, Calif., on Saturday, Dec. 31. Costello drove her car on the flooded street thinking she could make it when it stalled in the two feet of water. After two hours the water had receded about a foot making it easier to rescue her. Police were called but stood by and watched after calling in a tow truck to help pull the car out of the water. Nurse Katie Leonard, of Pleasant Hill, lives down the block used her kayak to bring Costello hot tea, blankets, food and a phone to call a friend. Jose Carlos Fajardo/Bay Area News Group via AP

Jose Carlos Fajardo

LOS ANGELES — California was drying out and digging out on New Year's Day after a powerful storm brought drenching rain or heavy snowfall to much of the state, snarling traffic and closing major highways.

Dozens of drivers were rescued on New Year's Eve along Interstate 80 near Lake Tahoe after cars spun out in the snow during the blizzard, the California Department of Transportation said. The key route to the mountains from the San Francisco Bay Area reopened early Sunday to passenger vehicles with chains.

“The roads are extremely slick, so let's all work together and slow down so we can keep I-80 open,” the California Highway Patrol said on Twitter. Several other highways, including State Route 50, also reopened.

In this image taken Saturday, Dec. 31, and released by California Highway Patrol Truckee, vehicles stranded are stranded along Interstate 80 at the Nevada State line and Colfax, Calif. Driving conditions are dangerous and treacherous, travel is not advised. There are dozens and dozens of vehicles stuck on the freeway and county roads. California was drying out and digging out on New Year's Day after a powerful storm brought drenching rain or heavy snowfall to much of the state, snarling traffic and closing highways. California Highway Patrol Truckee via AP

More than 4 feet of snow had accumulated in the high Sierra Nevada, and the Mammoth Mountain Ski Area said heavy, wet snow would cause major delays in chairlift openings. On Saturday, the resort reported numerous lift closings, citing high winds, low visibility and ice.

In the state's capital, crews cleared downed trees from roads and sidewalks as at least 33,000 customers were still without power Sunday, down from more than 150,000 a day earlier, according to a Sacramento Municipal Utility District online map.

A so-called atmospheric river storm pulled in a long and wide plume of moisture from the Pacific Ocean. Flooding and rock slides closed portions of roads across the state.

Rainfall in downtown San Francisco hit 5.46 inches on New Year's Eve, making it the second-wettest day on record, behind a November 1994 deluge, the National Weather Service said. Videos on Twitter showed mud-colored water streaming along San Francisco streets, and a staircase in Oakland turned into a veritable waterfall by heavy rains.

In Southern California, several people were rescued after floodwaters inundated cars in San Bernardino and Orange counties. No major injuries were reported.

With the region drying out on New Year's Day and no rainfall expected during Monday's Rose Parade in Pasadena, spectators began staking out their spots for the annual floral spectacle.

The rain was welcomed in drought-parched California. The past three years have been the state's driest on record — but much more precipitation is needed to make a significant difference.

It was the first of several storms expected to roll across the state in the span of a week. Saturday's system was warmer and wetter, while storms this week will be colder, said Hannah Chandler-Cooley, a meteorologist at the National Weather Service in Sacramento.

The Sacramento region could receive a total of 4 to 5 inches of rain over the week, Chandler-Cooley said.

Another round of heavy showers was also forecast for Southern California on Tuesday or Wednesday, the National Weather Service's Los Angeles-area office said.