LOS ANGELES -- Two people died in a submerged car, evacuations were ordered for wildfire-scarred California, and Seattle and Portland faced the rare chance of snowy streets as a wave of storms rolled through the U.S. West.

The new storms, which could drop rain and snow over much of the region into next week and plunge the Pacific Northwest into a lengthy cold snap, follow a now-departed atmospheric river that delivered copious amounts of precipitation this week.

On Thursday, two people died when their car was submerged in a flooded underpass in Millbrae, California, just south of San Francisco. Firefighters rescued two people who had climbed atop a car but they couldn't reach the fully submerged vehicle, San Mateo County sheriff's Det. Javier Acosta said.

In the Sierra Nevada, an evacuation warning was issued Thursday for about 150 homes downstream of Twain Harte Lake Dam after cracks were found in granite that adjoins the manmade part of the 36-foot-high (11-metre) structure.

The warning was lifted around 6 p.m. after inspectors determined the dam was structurally sound and clear it for continued use, according to a Facebook post by the Tuolumne County Sheriff's Office.

The Sierra range could see 5 to 8 feet (1.5 to 2.4 metres) of snow through the holidays, with 10 feet (3 metres) possible at higher elevations, and authorities urged people to avoid traveling through the mountain passes, which could be treacherous.

A winter storm warning issued Friday remains in effect until 10 a.m. Tuesday for most of the Sierra, where as much as 3 feet (91 centimetres) of snow had fallen early Friday at Mammoth Mountain south of Yosemite National Park. About 2 feet (61 cm) fell Thursday at some Tahoe-area ski resorts.

As much as 5 feet (1.5 metres) of new snow is possible by Tuesday on mountain tops around Lake Tahoe. One to 3 feet (30-91 cm) to is expected at lake level. Wind gusts over ridges could exceed 100 mph (160 kph), the National Weather Service said, making travel difficult to impossible.

In Southern California, evacuation orders were issued Thursday night in Orange County because of possible mudslides and debris flows in three canyons where a wildfire last December burned the ground bare. The Orange County Fire Authority reported a mudslide Thursday night in one canyon that affected some roads but no injuries were reported.

On Thursday, a slow-moving front dumped the most rain parts of eastern Nevada have seen on the date in more than a half century.

The Ely Airport near the Utah line set records for both rain and snow. The 0.61 inch (1.5 cm) of rain broke the old record of 0.55 (1.4 cm) set in 1955. The 3.6 inches (19 cm) of snow bettered 3 inches (7.6 cm) set in 2001.

A record 0.41 inch (1 cm) of rain fell at Eureka, smashing the old of 0.14 inch (40 millimetres) set in 1968.

In preparation for freezing temperatures, snow and ice in the Pacific Northwest this holiday weekend and next week, state officials in Oregon have declared an emergency and shelters are being opened throughout the region to help the homeless.

At least five severe weathers shelters in the Portland, Oregon, metro area will open starting at 3 p.m. on Christmas Day. And the city's public transportation service will befree for people who need to get to a shelter. Seattle city leaders will open two severe weather shelters in the evenings starting Saturday through at least Wednesday.

"Local government is working hard to get people to a warm, dry place but we can't be everywhere," Dr. Jennifer Vines, the health officer for Multnomah County -- home to Portland -- said Friday. "As with the heat event almost six months ago to the day, we are asking all county residents to check on others, direct individuals to warming shelters and help hand out gear to keep people warm -- and alive."

Recent forecasts show at least an inch of snow is likely to fall Sunday in the Seattle and Portland regions, which don't typically see snow.

But forecasters and state officials say the main concern is cold temperatures in the region, with daytime highs next week struggling to reach above freezing, that are likely to impact people experiencing homelessness and those without adequate access to heating.

Oregon Gov. Kate Brown issued a state of emergency declaration Thursday evening to remain in effect through Jan. 3, saying expected snow and sustained temperatures below freezing could result in critical transportation failures and disruptions to power and communications infrastructure.

Portland and Multnomah County earlier declared states of emergency.

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AP journalists Stefanie Dazio in Los Angeles, Sara Cline in Portland, Oregon, and Scott Sonner in Reno, Nevada, contributed to this report. Cline is a corps member for the Associated Press/Report for America Statehouse News Initiative. Report for America is a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues.