Dangerously cold temperatures affected much of the Rockies, Great Plains and Midwest on Tuesday, with wind chills below minus 34C (minus 30F) in many parts of the central US.
More than 120,000 US homes and businesses were without power early on Tuesday, most of them in Oregon, Texas and Louisiana, after widespread cuts that started Saturday.
Portland General Electric warned that the threat of freezing rain on Tuesday could delay restoration efforts.
Transport officials urged residents to avoid travel because roads were expected to be hazardously slick with ice that could weigh down trees and power lines, causing them to fall.
Classes were cancelled on Tuesday for school pupils in Portland and other major cities including Chicago – home to the nation’s fourth-largest public school district – Denver, Dallas, and Fort Worth, Texas.
The storms and frigid temperatures affected everything from air travel to NFL play-off games to Iowa’s presidential caucuses, and were also the cause of several deaths around the country.
At least four people in the Portland area died, including two people from suspected hypothermia, a man who was killed when a tree fell on his house, and a woman who died in a fire that spread from an open-flame stove when a tree fell on to a motor home.
In Wisconsin, the deaths of three homeless people in the Milwaukee area were under investigation, with hypothermia the likely cause, officials said.
A Kentucky State Police helicopter rescued four campers stranded on Courthouse Rock in the Red River Gorge area on Monday, according to Powell County Search and Rescue, which said the call was “one of the most dangerous rescues ever attempted in the Gorge”.
The Asbury College students were in good spirits “other than being cold”, officials said.
In Louisiana, state troopers worked all night to get motorists off bridges that iced over, stranding drivers on the spans, Louisiana State Police said.
Some of the biggest problems were on Interstate 10, including a stretch between Baton Rouge and Lafayette; and the Interstate 210 bridge near Lake Charles, authorities said.
Freezing rain and sleet was expected continue across portions of the Southeast into Tuesday morning.
Winter storm warnings were in effect for Lawrence, Limestone and Madison counties in Alabama and in Franklin County in Tennessee, south-east Arkansas, north-east Louisiana and much of northern, central and southwestern Mississippi.
Moderate to heavy snowfall was expected into the Mid-Atlantic on Tuesday morning with winter weather advisories in effect from the Mid-Atlantic into New England, according to the National Weather Service.
Another 2in-4in (5cm-10cm) of snow was expected in New York state and 6in-8in (15cm-20cm) was expected in upper New England until Wednesday.
In the Pacific Northwest, significant freezing rain was expected on Tuesday morning, with ice storm warnings in effect until Wednesday morning.
In parts of the Cascades into the Northern Rockies, 15in-28in (38cm-71cm) of snow was possible.
Another day of record cold temperatures was expected across much of the Rockies, Great Plains and Midwest on Tuesday, with wind chills below minus 30C (minus 22F) extending into the mid-Mississippi Valley, according to the National Weather Service.
Monday night saw temperatures drop as low as minus 12.2C (10F) in Olive Branch, Mississippi, and Jackson, Tennessee.
Frigid temperatures in the Northeast did not stop fans from heading out to cheer on the Buffalo Bills at a snow-covered Highmark Stadium in Orchard Park, New York.
The Bills beat the Pittsburgh Steelers on Monday in an AFC wild-card play-off game which was delayed for more than 27 hours because of a storm that dumped more than 2ft (61cm) of snow on the region.
And voters handed former president Donald Trump a win on Monday night in the coldest first-in-the-nation Iowa caucuses on record.
Temperatures dipped to minus 19.4C (minus 3F) in Des Moines, with the wind chill making it feel far colder.
Air travellers across the country suffered delays and cancellations. The flight tracking service FlightAware reported about 2,900 cancellations on Monday within, into or out of the United States.
Temperatures are expected to moderate midweek but a new surge of colder air is forecast to drop south over the Northern Plains and Midwest, reaching the Deep South by the end of the week.
