Dangerously cold temperatures affected much of the Rockies, Great Plains and Midwest on Tuesday, with wind chills below minus 30 degrees (minus 34.4 Celsius) in many parts of the central U.S.

More than 85,000 U.S. homes and businesses were without power early Tuesday, the bulk of them in Oregon after widespread outages that started Saturday. Portland General Electric warned that the threat of freezing rain Tuesday could delay restoration efforts. Transportation officials urged residents to avoid travel as roads were expected to be hazardously slick with ice that could weigh down trees and power lines, causing them to fall.

Classes were canceled Tuesday for students in Portland and other major cities including Chicago — home to the nation’s fourth-largest public school district — Denver, Dallas, Fort Worth, Texas, across New England and in the Washington, D.C., region. Federal offices in and around the the nation’s capital were also closed Tuesday.

The storms and frigid temperatures affected everything from air travel to NFL playoff 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. Another man was killed after a tree fell on his house and a woman died in a fire that spread from an open-flame stove after a tree fell onto an RV.

In Wisconsin, the deaths of three homeless people in the Milwaukee area were under investigation, with hypothermia the likely cause, officials said.

Freezing rain and sleet was expected to 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, southeast Arkansas, northeast 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 2 to 4 inches (5 to 10 centimeters) of snow was expected in New York state and 6 to 8 inches (15 to 20 centimeters) of snow was expected in upper New England through Wednesday.

In the Pacific Northwest, significant freezing rain was expected Tuesday morning, with ice storm warnings in effect through Wednesday morning. In parts of the Cascades into the Northern Rockies, 15 to 28 inches (38 to 71 centimeters) 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 30 extending into the mid-Mississippi Valley, according to the National Weather Service.

Monday night saw temperatures drop as low as 10 degrees (minus 12.2 C) in Olive Branch, Mississippi, and Jackson, Tennessee.

Frigid temperatures in the Northeast didn’t 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 playoff game that was delayed 27 1/2 hours because of a storm that dumped more than 2 feet (61 centimeters) of snow on the region.

And voters handed former President Donald Trump a win Monday night in the coldest first-in-the-nation Iowa caucuses on record. Temperatures dipped to minus 3 degrees (minus 19.4 C) in Des Moines, with the wind chill making it feel far colder.

Air travelers across the country experienced delays and cancellations. The flight tracking service FlightAware reported more than 3,300 cancellations Monday within, into or out of the United States and more than 1,200 cancellations were already reported by daybreak Tuesday on the East Coast.

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.

(AP)