Polar vortex: -46C temperatures turn Chicago River to ice

A blast of Arctic air from the polar vortex has caused temperatures to drop to as low as -46C (-28F) in Chicago. Cities in the midwest opened warming shelters as temperatures plummeted well below zero. The Illinois governor warned the weather ‘poses a serious threat’ to people’s wellbeing. The polar vortex, a mass of freezing air, usually spins around the North Pole
Polar vortex blasts US with life-threatening cold