Subfreezing temperatures across much of the US left millions of Americans facing dangerous cold as Arctic storms left four dead and knocked out electricity to tens of thousands in the Northwest, brought snow to the South, and walloped the Northeast with blizzard conditions that forced the postponement of an NFL game.

An estimated 95 million people nationwide faced weather warnings or advisories Sunday for wind chills below zero Fahrenheit (minus 17 Celsius). Forecasters said the severe cold was expected to push as far south as northern Texas while the bitter blast sends wind chill readings as low as minus 70 degrees (minus 56 Celsius) in Montana and the Dakotas.

"It takes a matter of minutes for frostbite to set in," the South Dakota Department of Public Safety said in a statement on Sunday urging people to stay indoors.

In Buffalo, New York, where snowfall of 1 to 2 feet was forecast, severe conditions led officials to postpone the Buffalo Bills-Pittsburgh Steelers NFL playoff game from Sunday to Monday. Winds whipped at 48 kilometres per hour, and snow was falling at a rate of 2 inches per hour.

Workers with shovels and trucks worked to clear snow from the field at Buffalo's Highmark Stadium as the Bills warned volunteers eager to help with the shovelling to stay at home and not defy a travel ban on area roads.

"Looks like a pretty good day to not have a football game," New York Governor Kathy Hochul, a Buffalo native, posted on X with a video clip of whiteout conditions in the western New York city.

Zack Taylor, a National Weather Service meteorologist in College Park, Maryland, warned some parts of the Northeast would see intense snowfall and extreme winds, with gusts up to 89 kilometres per hour possible.

"That's why they're expecting to see near-blizzard conditions at times," Taylor said.

Across the country in Oregon, more than 130,000 homes and businesses were without electricity, most of them in the Portland metro area, a day after high winds and a mix of snow and ice brought down trees and power lines.

"Given the extent of the damage and the high level of outage events, restoration efforts will continue into the week and customers are encouraged to plan accordingly," Portland General Electric said in a statement.

The City of Portland Bureau of Environmental Services said its crews were working non-stop at multiple locations to make emergency repairs and prevent sewage releases into homes and businesses.

Widespread power outages affecting tens of thousands were also reported Sunday in Michigan, New York, Pennsylvania and Wisconsin. In Nebraska, the Omaha Public Power District asked customers to conserve electricity to prevent outages.

"The weather came on faster and has been more prolonged than anticipated," the district said in a statement on Sunday.

Airports across the country were impacted. More than half of flights into and out of Buffalo Niagara International Airport were cancelled. Scores of flights also were canceled or delayed at Chicago, Denver and Seattle-Tacoma airports.

Forecasters also warned that rapid bursts of heavy snow and wind could cause drastic and sudden drops in visibility in eastern Pennsylvania and parts of northern New Jersey and Delaware with some "near whiteout conditions" possible.

Another Arctic storm that's dumped heavy snowfall in the Rockies was forecast to push further south, potentially bringing 4 inches to 6 inches of snow to parts of Arkansas, northern Mississippi and west Tennessee.

Much of Wisconsin were under advisories through Monday afternoon, with predicted wind chills as low as 30 degrees below zero (minus 34 Celsius).

Even parts of northern Louisiana, Alabama and Georgia could see snow. In Shreveport, Louisiana, Mary Trammel was among residents who stocked up on bottled water, food and fuel for generators ahead of subfreezing weather expected to coat some roads in ice and up to an inch of snow.

"It's cold out here," said Tramel, who told KSLA-TV she bought bread and ingredients for enough soup to last days.

Arkansas Governor Sarah Huckabee Sanders declared a state of emergency in advance to give utility trucks and trucks hauling essential supplies greater flexibility to respond.

Officials in Mississippi's capital city of Jackson were preparing for days of freezing weather after cold snaps in 2021 and 2022 caused pipes to burst and water pressure to drop across the city of 150,000.

"We feel as confident as we can that we're prepared for whatever comes our way," Ted Henifin, Jackson's interim manager of Jackson's long-troubled water system, told WAPT-TV.

The wild weather didn't just bring snow and ice. Record high tides that flooded some homes in Maine and New Hampshire on Saturday also swept three historic fishing shacks into the sea from where they had stood for more than 130 years in South Portland, Maine.

In Oregon, just south of Portland, 100 trees toppled on Saturday, including one that fell on a house and killed a man. Two other people died of suspected hypothermia and a fourth died in a fire that spread from an open-flame stove after a tree fell onto an RV.

The snow and gusting winds had let up Sunday in Oregon, but frigid temperatures meant roads remained treacherous and much of Portland was shut down. In nearby Lake Oswego, Glenn Prohaska was looking for a business that had WiFi so he could book a hotel. With the power out, the temperature in his home had dropped to the 20s overnight.

"In the 40 years I've been here, this is the worst I've seen," he said.