Katie Mettler Christopher Ingraham Samantha Schmidt Angela Fritz The Washington Post

Polar vortex: Nearly 90 million people are likely to experience temperatures at or below zero in the Midwest and New England, according to the National Weather Service; 25 million of them will face temperatures below minus-20 - dips that when combined with wind can cause frostbite in a matter of minutes.

Polar vortex: Nearly 90 million people are likely to experience temperatures at or below zero in the Midwest and New England, according to the National Weather Service; 25 million of them will face temperatures below minus-20 - dips that when combined with wind can cause frostbite in a matter of minutes.