UK & World News
Polar Vortex Sends US Into Deep Freeze Again
Arctic winds are expected to blast much of the United States as the polar vortex tightens its grip on the country for the third time this winter.
Forecasters have warned that temperatures will be up to 30F (17C) colder than normal, falling to -10F (-23C) in places like Minneapolis, Minnesota.
About two-thirds of the country is on alert for the latest bout of bitter weather as it spreads southwards.
Warnings are in place for several states, including in Wisconsin, where blizzard conditions are expected.
Sky News weather presenter Isobel Lang said: "Cold air is surging south again across parts of the United States, with top temperatures of around -13C in Chicago on Thursday.
"As it moves towards the eastern seaboard towards the end of the week, so the temperatures will plunge below freezing in places like New York as well."
She added: "With no real let-up in that winter weather, it does look as though it'll stay cold throughout the weekend, with snow at times, too."
The sub-zero temperatures have been triggered by the polar vortex - a rotating pool of cold, dense, air held in place by a belt of strong winds.
This year, the belt has loosened, letting polar air slip as far south as Alabama.
When the vortex first struck with ferocious force in early January, record low temperatures left at least 21 people dead.
The iconic Niagara Falls on the US-Canada border froze over, leaving long icicles dangling above the river below.
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