America snowed under as cold weather looks set to continue

A polar vortex - as it's called - is expected to bring dangerously cold, record low temperatures to the US early this week.

Blue = hard freeze warning, pink = winter storm warning, red= blizzard warning Credit: National Weather Service

The rotating pool of cold, dense, Arctic air, has come unusually far south and is expected to bring temperatures as cold as -50 C.

Boston airport was forced to ground flights as the snow set in. Credit: Reuters

People in parts of the Midwest are being urged to stay indoors and stock up on food because frostbite and hypothermia can set in very quickly when bare skin is exposed to such low temperatures.

The snow storm has already covered Detroit, in Michigan. Credit: Reuters

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