BUFFALO, N.Y. (AP) — Millions of people hunkered down in a deep freeze overnight and early Christmas morning to ride out the frigid storm that has killed at least 24 people across the United States, trapping some residents inside homes with heaping snow drifts and knocking out power to several hundred thousand homes and businesses.

The scope of the storm is nearly unprecedented, stretching from the Great Lakes to the Rio Grande. About 60% of the U.S. population faced some sort of winter weather advisory or warning, and temperatures plummeted drastically below normal from east of the Rocky Mountains to the Appalachians, the National Weather Service said.

Some 1,346 domestic and international flights were canceled as of early Sunday, according to the tracking site FlightAware.

Forecasters said a bomb cyclone — when atmospheric pressure drops very quickly in a strong storm — had developed near the Great Lakes, stirring up blizzard conditions, including heavy winds and snow.

The storm unleashed its full fury on Buffalo, with hurricane-force winds and snow causing whiteout conditions, paralyzing emergency response efforts — New York Gov. Kathy Hochul said almost every fire truck in the city was stranded — and shutting down the airport through Monday, according to officials. The National Weather Service said the snow total at the Buffalo Niagara International Airport stood at 43 inches at 7 a.m. Sunday.

Two people died in their homes in Cheektowaga, New York, when emergency crews could not reach them in time to treat their medical conditions, and another died in Buffalo. Four more deaths were confirmed overnight, bringing the Erie County total to seven. County Executive Mark Poloncarz warned there may be more deaths.

“Some were found in cars, some were found on the street in snowbanks,” said Poloncarz. “We know there are people who have been stuck in cars for more than 2 days.”

Freezing conditions and day-old power outages had Buffalonians scrambling to get out of their homes to anywhere that had heat. But with city streets under a thick blanket of white, that wasn’t an option for people like Jeremy Manahan, who charged his phone in his parked car after almost 29 hours without electricity.

“There’s one warming shelter, but that would be too far for me to get to. I can’t drive, obviously, because I’m stuck,” Manahan said. “And you can’t be outside for more than 10 minutes without getting frostbit.”

Ditjak Ilunga of Gaithersburg, Maryland, was on his way to visit relatives in Hamilton, Ontario, for Christmas with his daughters Friday when their SUV was trapped in Buffalo. Unable to get help, they spent hours with the engine running in the vehicle buffeted by wind and nearly buried in snow.

By 4 a.m. Saturday, with their fuel nearly gone, Ilunga made a desperate choice to risk the howling storm to reach a nearby shelter. He carried 6-year-old Destiny on his back while 16-year-old Cindy clutched their Pomeranian puppy, stepping into his footprints as they trudged through drifts.

“If I stay in this car I’m going to die here with my kids,” he recalled thinking, but believing they had to try. He cried when the family walked through the shelter doors. “It’s something I will never forget in my life.”

The storm knocked out power in communities from Maine to Seattle. But heat and lights were steadily being restored across the U.S. According to poweroutage.us, fewer than 300,000 customers were without power at 5 a.m. Pacific time on Sunday – down from a peak of 1.7 million.

Across the six New England states, about 121,300 customers remained without power on Sunday, with Maine still the hardest hit.

Storm-related deaths were reported in recent days all over the country: seven in Erie County, New York; 10 dead in multiple crashes in Ohio, including a pileup involving some 50 vehicles, a man whose sport utility vehicle ran into a snowplow and an electrocuted utility worker; four motorists killed in separate crashes in Missouri and Kansas; a Vermont woman struck by a falling branch; an apparently homeless man found amid Colorado’s subzero temperatures; a woman who fell through Wisconsin river ice.

In Florida, the thermometer plunged below freezing for the first time in almost five years at Tampa International Airport, and temperatures dropped into the 20s and 30s in other parts of central Florida area, according to the National Weather Service.

In South Florida, temperatures dropped to as low as 43 degrees in West Palm Beach. The temperature drop was conducive to iguanas falling out of trees since the cold-blooded reptiles typically become immobilized in unusually cold weather.

Along Interstate 71 in Kentucky, Terry Henderson and her husband, Rick, weathered a 34-hour traffic jam in a rig outfitted with a diesel heater, a toilet and a refrigerator after getting stuck trying to drive from Alabama to their Ohio home for Christmas.

“We should have stayed,” Terry Henderson said after they got moving again Saturday.

Vivian Robinson of Spirit of Truth Urban Ministry in Buffalo said she and her husband have been sheltering and cooking for 60 to 70 people, including stranded travelers and locals without power or heat, who were spending Saturday night at the church.

Many arrived with ice and snow plastered to their clothes, crying, their skin reddened by the single-digit temperatures.

“It’s emotional just to see the hurt that they thought they were not going to make it, and to see that we had opened up the church, and it gave them a sense of relief,” Robinson said. “Those who are here are really enjoying themselves. It’s going to be a different Christmas for everyone.”