NASHVILLE – Much of the middle of the United States was girding itself on Wednesday for an extraordinarily brutal mix of frigid temperatures, blowing snow and high winds set to arrive just at the peak period of Christmas-season travel.

The combination of a rapidly intensifying storm system called a “bomb cyclone” and a large arctic air mass will bring blizzard conditions and extremely dangerous wind chills to the Plains and Midwest, as well as freezes and high winds that will disrupt travel across the eastern half of the country before the holiday weekend, forecasters said.

As the powerful storm approaches, the warnings have grown increasingly ominous. Even in places where bitter cold and heavy snowfall are facts of life this time of year, officials and forecasters have cautioned residents to expect something particularly severe.

In Buffalo, New York, the National Weather Service described the coming event as a “once-in-a-generation storm”.

In Cheyenne, Wyoming, forecasters said the cold front had swept in and immediately broken records as the temperature dropped from 6 deg C to minus 16 deg C in a half-hour.

The conditions arrive at a particularly inopportune moment, coming during a busy week of holiday travel, towards the end of Hanukkah and extending through Christmas Day on Sunday.

The storm could most likely lead to substantial flight delays and cancellations at some of the country’s busiest airports and create havoc on the roads.

Wind chills as low as minus 57 deg C are possible in the High Plains, and subzero to single-digit temperatures are expected throughout much of the Midwest, forecasters said.

In the Central and Southern Plains, a cold front is expected to sweep through the region from Wednesday to Friday, causing dramatic temperature declines of as much as minus 7 deg C within hours, which could bring flash freezes to roads, the National Weather Service warned. The Great Lakes may see more than 30cm of snowfall between Wednesday evening and Friday.

In West Fargo, North Dakota, Ostrom’s Hardware has been quickly selling through its supply of snow shovels, snowblowers and ice melt.

“Yesterday, we had no shovels on our racks,” said the store’s assistant manager Levi Kraig.

Cities across the Midwest, including Cleveland and Peoria, Illinois, prepared to open warming centres to allow residents to seek shelter during the storm. NYTIMES