SIOUX FALLS (South Dakota) — Bitterly cold temperatures blowing into the American Midwest and North-east in the coming days are likely to set records, disrupt schools along with airports and endanger those who go outside without proper clothing.

The frigid air will continue early this week, funnelled as far south as the Gulf Coast because of what one meteorologist called a “polar vortex”, a counter-clockwise-rotating pool of cold, dense air.

“It’s just a large area of very cold air that comes down, forms over the North Pole or polar regions ... usually stays in Canada, but this time it’s going to come all the way into the eastern United States,” said National Weather Service meteorologist Phillip Schumacher in Sioux Falls, South Dakota.

The forecasts are startling: Minus 31°C in Fargo, North Dakota, minus 35°C in International Falls, Minnesota, and minus 26°C in Indianapolis and Chicago. At those temperatures, exposed skin can get frostbitten in minutes and hypothermia can quickly set in as wind chills may reach minus 45.5°C, minus 51°C or even minus 56.7°C.

Already, parts of the north-eastern New England states have dropped into the negatives, with East Brighton, Vermont, seeing minus 34.4°C and Allagash, Maine, hitting minus 37.8°C. The cold will sweep through other parts of New England, where residents are digging out from a snowstorm.

It has not been this cold for decades — 20 years in Washington DC, 18 years in Milwaukee, 15 in Missouri — even in the Midwest, where bundling up is second nature. Weather Bell meteorologist Ryan Maue said: “If you’re under 40 (years old), you’ve not seen this stuff before.”

“The last really big Arctic outbreak was 1994,” said Mr Bob Oravec, a forecaster with the National Weather Service. “Outbreaks like this don’t occur every day.”

“A person not properly dressed could die easily in those conditions,” said National Weather Service meteorologist Scott Truett in St Louis, describing the expected wind chill in Missouri at daybreak today.

The Arctic chill will affect everything from sports to schools to flights. Mr Mike Duell, with flight-tracking website FlightAware.com, says to expect airport delays and flight cancellations because of the cold temperatures.

“For some of them, they run into limitations on the aircraft. They’re only certified to take off at temperatures so low, so if they get into a particular cold front, it can prevent them from being able to legally take off,” he said. “In a lot of cases, it’s just ice.”

Minnesota has called off school today for the entire state — the first such closing in 17 years — as well as the Wisconsin cities of Milwaukee and Madison. The South also will dip into temperatures rarely seen. By today morning, western and central Kentucky could be below zero — “definitely record-breaking”, said weather service meteorologist Christine Wielgos in Paducah, Kentucky.

In north-eastern Canada, about 110,000 customers were without power due to a transformer fire on Saturday linked to heavy snow, government officials and Newfoundland and Labrador Hydro said. AGENCIES