Millions of California residents are under a freeze warning, with a state of emergency declared in over a dozen counties to deal with a string of brutal winter storms.
Rescue crews are working all hours to dig out communities in mountainous regions cut off by deep snow.
An 80-year-old woman died after her porch collapsed under heavy snow, CBS News reports.
The state’s popular Yosemite National Park has been closed indefinitely.
“Park crews are working to restore critical services so visitors can safely return,” park officials said.
Record-breaking snowfall forced the park to close last week. It was scheduled to reopen on Thursday.
On Wednesday night, Governor Gavin Newsom declared a state of emergency for 13 counties to push the pace of disaster response and relief.
“The state is also contracting with private companies to accelerate snow removal and clear roadways, and is coordinating with investor-owned utilities to rapidly restore power,” Newsom’s office said in a statement.
More than 75,000 residents and businesses in California were without power as of Thursday morning, according to tracking site poweroutage.us.
In San Bernardino County east of Los Angeles, around-the-clock snow removal is underway but it could take more than a week to reach some areas, Dawn Rowe, chair of the county’s board of supervisors, told the Associated Press.
The National Guard is expected to arrive in the San Bernardino Mountains on Thursday. Local media reported the Guard’s specialised Joint Task Force Rattlesnake, which often helps to fight wildfires, are scheduled to arrive by mid-afternoon local time.
Some areas are dealing with as much as seven feet of snow, and authorities have conducted 17 rescue operations to help off-roaders and skiers.
Many residents remained trapped in their homes in the San Bernardino Mountains on Wednesday. The county has set up a hotline for residents dealing with issues like frozen pipes, roof problems and food shortages.
“We know that roofs are starting to collapse (by the weight of the snow),” Ms Rowe told the AP. She warned businesses would be affected.
Mariam Magana and her family have been snowed in at their Crestline Airbnb for nearly a week – and their food rations are running low, she told CBS News, the BBC’s US partner.
“Our three-day vacation turned into a horrific nightmare,” she said.
Their cars are buried in seven feet of snow, and they have called the county’s emergency line and California Highway Patrol – but help has yet to arrive.
She said they were also concerned about access to medication after her children have had to use both EpiPens – prescribed to people with potentially serious allergies – they had available.
Also in Crestline, snowfall caused the roof of Goodwin and Sons Market to collapse as safety inspectors were watching. Officials salvaged what they could from the market for residents in need.
“We know many of you are counting on us and we will do everything we can to get open as soon as possible,” the market said in a Facebook post.
One resident shared photos of his nearly six-mile trek through the snow for groceries on Twitter.
To feed his family of five, he used a sled to transport groceries through the snow since his street remained snowed in.
The National Weather Service forecasts some relief over the next few days with dry conditions expected. But temperatures will remain below average.
“There is potential for record low morning temperatures Thursday across portions of central and northern California,” the NWS said in a statement.
More than 18 million people across California were under a freeze warning as of Thursday morning.
More snow was forecast for the weekend, including up to two feet in the Yosemite area.
The same forecast predicts record high temperatures across the Gulf Coast on Thursday and across portions of Florida on Friday.