By Tyler Clifford

DETROIT (Reuters) – An Arctic blast surged across a wide swath of the United States on Wednesday, gripping much of the nation with bitter cold and life-threatening wind chills ahead of a powerful winter storm expected to complicate holiday travel for millions of Americans.

About 200 million people in the Lower 48 states were under extreme weather alerts as a freezing air mass descended from the Northern Plains, sending temperatures into a nosedive, said Bob Oravec, a forecaster with the National Weather Service (NWS).

Temperatures in Denver, for example, plunged on Wednesday – the first official day of winter – from a daytime high of 51 Fahrenheit (10 Celsius) into the low-single digits by evening. The mercury was expected to sink below zero by Thursday morning.

The Weather Service reported the temperature plummeted by 37 degrees in one hour at Denver International Airport – from 42F to 5F – a record drop at that location.

“That’s the kind of changes that are going to be occurring as this front pushes southward: rapid temperature drops, sometimes 50 or more degrees colder than the previous day,” Oravec said. “It’s a pretty powerful, powerful system.”

The extreme weather coincided with the start of a holiday travel season shaping up as one of the busiest in decades. Nearly 113 million people could travel more than 50 miles (30 km) from their homes beginning Friday, according to the American Automobile Association, assuming winter conditions don’t scupper their plans.

“We had a great Thanksgiving week with minimal disruption. Unfortunately, it’s not going to be that way going into Christmas,” U.S. Transportation Secretary Pete Buttigieg told MSNBC.

The impending storm, fed by moisture from the Great Lakes, could dump up to a foot (0.3 m) of snow on the Upper Midwest between Wednesday and Friday, with blizzard conditions stretching from the Northern Plains states to the Great Lakes region.

By Thursday night, a so-called “bomb cyclone” will likely form as the strong Arctic front sweeps across the Great Lakes, driving temperatures to record-breaking lows on the Gulf Coast and the eastern United States by Friday, Oravec said.

Wind-chill and hard-freeze warnings extended through much of Texas, Louisiana and Alabama, with a hard-freeze watch posted for the Florida panhandle.

DANGEROUS TEMPERATURES

Freezing weather and sub-zero wind chills, cold enough to induce frostbite on exposed skin within minutes, dominated much of the nation’s forecast heading into the holiday weekend.

Wind-chill values dropping to minus 40F were expected across a vast swath of the West, from the Cascades to the Rockies and into the northern and central Plains, with some localized areas seeing wind chill plunging as far as 70 degrees below zero through week’s end, the Weather Service said.

The extreme cold poses a particular danger to livestock in the ranching-intensive region, the NWS warned.

Wind-chill values as low as minus 15F (minus 26C) were forecast after Thursday evening around the Dallas-Fort Worth area, the NWS said.

The storm will test the Texas power grid’s new winterization measures. Hundreds of Texans died in February 2021 after wintry storms overburdened the state’s grid and millions of customers lost power.

Officials at the Electric Reliability Council of Texas, which runs most of the state’s power supply, said this week they were confident the grid could handle increased demand.

Heavy rains, strong winds and coastal flooding were in store for parts of the Northeast on Thursday and Friday. The Arctic front will then arrive, causing wet roadways to freeze and ice to form on power lines.

North Carolina and Kentucky both declared a state of emergency, West Virginia issued a state of preparedness and Colorado activated 100 National Guard troops in preparation for extreme weather.

A growing list of more than 2,000 U.S. flights scheduled between Wednesday and Friday, including service into and out of the country, have been canceled, according to the flight-tracking service FlightAware.

U.S. airlines including Delta, United Airlines and American Airlines announced on Tuesday they are waiving change fees and fare differences for passengers in a range of affected areas.

(Reporting by Tyler Clifford in Detroit; Additional reporting by Keith Coffman in Denver, Susan Heavey in Washington, Jonathan Allen in New York and Steve Gorman in Los Angeles; Editing by Jonathan Oatis, Aurora Ellis and Tom Hogue)

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