Tens of millions of Americans are enduring bone-chilling temperatures, blizzard conditions, power outages and cancelled holiday gatherings from a winter storm that forecasters said was nearly unprecedented in its scope, exposing about 60 per cent of the US population to some sort of winter weather advisory or warning.

More than 200 million people were under an advisory or warning today, the National Weather Service said.

The weather service’s map “depicts one of the greatest extents of winter weather warnings and advisories ever”, forecasters said.

Power outages have left more than 1.4 million homes and businesses in the dark, according to the website PowerOutage, which tracks utility reports.

And more than 4100 flights within, into or out of the US have been cancelled today, according to the tracking site FlightAware, causing more mayhem as travellers try to make it home for the holidays. Some airports, including Seattle-Tacoma International Airport, closed runways.

The huge storm stretched from border to border. In Canada, WestJet cancelled all flights at Toronto Pearson International Airport, beginning at 9am. And in Mexico, migrants waited near the US border in unusually cold temperatures as they awaited a US Supreme Court decision on whether and when to lift pandemic-era restrictions that prevent many from seeking asylum.

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.

Even though fleets of snowplows and salt trucks have been deployed, driving was hazardous and sometimes deadly. In Kansas City, Missouri, a minivan driver died after losing control on icy streets and overturning into a creek, police said.

State police in Michigan said in tweets that nine tractor-trailers crashed on Interstate 94 in Berrien County in the western part of the state and that a firefighter was struck in a separate location in the county while conducting traffic. The firefighter had unknown injuries.

Activists also were rushing to get the homeless out of the cold. Nearly 170 adults and children were keeping warm in Detroit at a shelter and a warming centre that are designed to hold 100 people.

“This is a lot of extra people” but “you can’t” turn anyone away, said Faith Fowler, the executive director of Cass Community Social Services, which runs both facilities.

In Chicago, Andy Robledo planned to spend the day organising efforts to check on unhoused people who have received tents, propane heaters and other supplies through his nonprofit, Feeding People Through Plants.

Robledo and volunteers build the tents modelled on ice-fishing tents, including a plywood subfloor.

“It’s not a house, it’s not an apartment, it’s not a hotel room. But it’s a huge step up from what they had before,” Robledo said.

In Portland, Oregon, officials opened five emergency shelters. It was so cold in the city that Taylor Bailey lost all sensation in her hands as she cycled to her job at at iconic bike rental, repair and touring store Cycle Portland in the frigid temperatures.

“It’s the wind, really, that’s so cold. The wind is absolutely bitter,” she said, adding that even her gloves didn’t help.

All bus service was suspended in the greater Seattle area due to an ice storm that made travel treacherous.

In far northern Indiana, where four counties remain under a blizzard warning, between 2 and 6 inches of snow (5-15cm) had fallen by Friday morning, but lake effect snow rolling off Lake Michigan could boost storm totals to well over a foot in some areas by Sunday, said Mark Steinwedel, a meteorologist with the National Weather Service in Syracuse, Indiana.

“It’s just nonstop lake effect snow and it’s really going to add up,” he said, predicting “pretty awful travel”.

The weather service is forecasting the coldest Christmas in more than two decades in Philadelphia, where school officials shifted classes online on Friday. Some surrounding districts cancelled classes altogether.

In South Dakota, Governor Kristi Noemactivated the state’s National Guard to haul firewood from the Black Hills Forest Service to the Rosebud Sioux Tribe as some members were stranded in their homes with dwindling fuel.

Rows of headstones at the North Dakota Veterans Cemetery are blanketed by snow in Mandan. Photo / via AP

Scot Eisenbraun, who runs a farm and ranch near Wall in western South Dakota, said he’s lost several cattle in recent days. The cold is life-threatening if you are caught outside, he said, so people travel in groups of two vehicles in case one gets stranded.

In Maine, gusts approaching 113km/h were reported along the coast. Atop New Hampshire’s Mount Washington, the tallest peak in the Northeast, the wind topped 210km/h.

It was so bad in Vermont that Amtrak cancelled service for the day, and nonessential state offices were closing early.

“I’m hearing from crews who are seeing grown trees ripped out by the roots,” Mari McClure, president of Green Mountain Power, the state’s largest utility, said at a news conference.

In eastern Iowa, sports broadcaster Mark Woodley became a Twitter sensation after he was called on to do live stand-ups in the wind and snow because sporting events were called off. By midday Friday, a compilation of his TV stand-ups had been viewed nearly 5 million times on Twitter.

“I’ve got good news and I’ve got bad news,” he told an anchor. “The good news is that I can still feel my face right now. The bad news is, I kind of wish I couldn’t.” - AP