A dangerous mass of arctic air is marching toward the South and East after leaving much of the Midwest miserable with wind chills as low as minus 55.
Wind chill warnings stretched as far south as Alabama and Florida, and schools in places such as Atlanta were canceled Tuesday. Officials in Maryland worried that roads wet from melting snow would freeze as temperatures fell.
Tennessee utility officials braced for near-record power demand, while Ohio prepared for its coldest temperatures in decades.
The polar air broke temperature records in Chicago, Fort Wayne, Ind., Oklahoma and Texas on Monday.
National forecasters say more than 187 million people could be affected by the weather system before it departs by week's end.