LOS ANGELES (AP) — Emergency crews in California scrambled Wednesday to shuttle food and medicine to mountain communities stranded by back-to-back winter storms that have dumped so much snow some residents can barely see out their windows.

In San Bernardino County east of Los Angeles, around-the-clock plowing is underway but it could take more than a week to reach some areas, said Dawn Rowe, chair of the county’s board of supervisors. With as much as 4 to 5 feet (122 to 152 centimeters) of new snowfall late Tuesday, sheriffs’ authorities have conducted 17 rescue operations to help off-roaders and skiers and emergency crews are trying to reach residents who need assistance.

“We know that roofs are starting to collapse,” Rowe said.

There were no reports of injuries. The county did not immediately have an estimate for how many roofs or decks may have fallen in, said David Wert, a county spokesman.

The San Bernardino Mountains are a major tourism and recreation destination but also home to a large year-round population in small cities and communities around lakes and scattered along winding roads. About 80,000 people live either part- or full-time in the snow-covered communities affected, Wert said.

Residents of these towns have been grappling with so much snow they’re running out of space to put it; clearing one area adds heaps to another. Grocery shelves were bare of some items, like bread, and running low on eggs and milk Tuesday as many residents made their way on foot to stores hoping to stock up on vital necessities. Cars remained buried under snow and roads closed to traffic.

Anthony Cimino, a 51-year-old retiree, said he’s been snowed in for about a week in the mountain community of Running Springs. He finally managed to clear his decks, but not for long.

“I woke up this morning and there was another two-and-a-half feet on them,” he said. “It was kind of like Groundhog Day.”

Another dumping of heavy snow in areas around Portland, Oregon, forced some school districts to close or hold remote classes on Wednesday. Over the past week, historic snowfall, ice and cold temperatures brought much of the city to a standstill, trapping drivers on roads and highways, paralyzing government services and leading to at least two suspected hypothermia deaths.

While California grappled with wintry weather, forecasters warned a new, powerful weather system will affect most of the lower 48 states this week. Six to 12 inches (15 to 30 centimeters) of snow could eventually fall in upstate New York, Vermont and New Hampshire, meteorologist David Roth said.

At the opposite end of the spectrum, record high temperatures were expected Wednesday along the Gulf Coast and into the Ohio Valley while the southern Plains to the mid-South braced for possible tornadoes Thursday, according to the National Weather Service.

Back in Southern California, two highways opened for traffic heading down from the mountains and the California Highway Patrol began escorting residents back up to their homes. Northwest of Lake Tahoe, on the California-Nevada border in the Sierra Nevada, an avalanche struck a three-story apartment building Tuesday evening, according to the local sheriff’s office. No injuries were reported.

The heavy snow was expected to end in California Wednesday afternoon after an additional 1 to 2 feet falls (30 to 60 centimeters), according to the weather service. In Arizona, snow began falling Wednesday morning as the storm moved eastward and was poised to dump as much as 2 feet (60 centimeters) of snow in northern Arizona by Thursday morning.

The Sierra snowpack provides about a third of California’s water supply. Tuesday’s water content of the snowpack — in a state grappling with years of drought — was 186% of normal to date, according to the state Department of Water Resources’ online data.

The next, larger weather system was expected to spread across much of the country Thursday, and areas such as the lower Mississippi Valley and Tennessee Valley could see heavy rain, thunderstorms and some flash flooding. The high temperatures could top 100 degrees (38 Celsius) across far south Texas, and windy, dry conditions would make for a critical risk of wildfire in parts of the Southwest for the next few days, according to the weather service.

Recent storms across the country have delayed travel, shuttered schools and overwhelmed crews trying to dig out of the snow and repair downed power lines. More than 60,000 customers were without power Wednesday morning in Michigan, which is still recovering from ice storms, and about 105,000 customers were in the dark in California, according to PowerOutage.us.

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Taxin reported from Orange County, California. Associated Press writers Claire Rush in Oregon, Walter Berry in Arizona and Trisha Ahmed in St. Paul, Minnesota, in contributed to this report.

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