The polar vortex of ultra-cold air usually spins around the North Pole, but it sometimes plunges south into the U.S., Europe and Asia. Studies show that a fast-warming Arctic is partly to blame for the increasing frequency of the polar vortex extending its grip.

Temperatures plunged into the teens and single digits in some spots, and the snow-dusted winds are driving the wind chill below zero. The polar vortex, a swirling mass of Arctic air typically contained over the North Pole, has pushed south, driving bone-chilling temperatures into the eastern United States.

A huge swath of the U.S. was blasted with ice, snow and wind on Monday as the polar vortex that dipped south over the weekend kept much of the country east of the Rockies in its frigid grip, making many roads treacherous,