'Polar vortex' to bring temperatures of -31C to the US

Icy, snow-covered roads and high winds have made travel treacherous from the Dakotas to Michigan and Missouri as much of the US prepared for dangerously cold temperatures that could break records.

A whirlpool of frigid, dense air known as a “polar vortex” was expected to suppress temperatures in more than half of the continental US beginning today and tomorrow, with wind chill warnings stretching from Montana to Alabama.