Polar Vortex To Plunge US Temperatures to -60C
Windchills of nearly -60C (-70F) are threatening to turn states in the north and northwest US into an icy deep freeze.
A phenomena described as a polar vortex is set to suck super-chilled air from the Arctic into North and South Dakota, the Great Lakes states and New England, sending temperatures plunging.
Washington DC has already seen its coldest temperatures for 20 years and several Mid Western states have recorded their lowest mercury readings for more than a decade.
Weather Bell meteorologist Ryan Maue described current weather conditions as a once in a generation event.
"If you're under 40 (years old), you've not seen this stuff before," he said.
But with much of the north east of the country already under thick snow and well below zero, a newly emerging weather system is threatening to cause further misery.
The 'polar vortex' is an anti-clockwise rotating pool of cold, dense air that forms close to the North Pole, but typically hangs over Canada.
Meteorologists say that unusually, this year, it is heading south and moving towards the north and eastern United States.
Fargo in North Dakota is expected to dip to -31C (-25F), International Falls, Minnesota will fall to -35C (-31F) and Indianapolis, Indiana and Chicago, Illinois, will reach -26C (-15F).
Forecasters say that at those temperatures exposed skin can get frostbitten in minutes and hypothermia can quickly set in as wind chills may reach 50, 60 or even 70 below zero F (45.5, 51 or even 56.7 below zero C).
Parts of northeastern New England have already dropped into the negatives with some places hitting -35C (-30F) in Vermont and -38C (-36F) in Maine.
TV pictures from some of the worst affected areas have been reminiscent of images from an Antarctic or Arctic winter.
At least 16 deaths have been blamed on a snow storm that swept across the eastern half of the US at the end of last week.
Only a few thousand people have been left without power in the US despite heavy snowfalls, but in Canada, which has seen unusually heavy snow in a country used to cold winters, nearly 90,000 are without power in Newfoundland.
Temperatures were also expected to plummet to -35C in northwestern Ontario and Environment Canada issued a special weather statement on Saturday night for much of southern Ontario, warning of heavy snowfalls.
Meanwhile, in Brazil, soaring temperatures in Rio de Janeiro set off fire sprinklers in shopping malls as the thermometer topped 40C (102F).
Thousands headed to the beach as temperatures rose to more than 50C in the sunshine.