Severe weather is expected to bring subzero temperatures the northern Plains as soon as Thursday, then reach the Mississippi Valley, the Northeast and the Ohio Valley by Sunday.

Heavy snow, sleet and freezing rain are slamming large parts of the U.S. as the dangerously cold weather causes major power outages and travel disruptions.

Severe to catastrophic ice accumulation is possible and could lead to prolonged power outages, worsen the impacts of the cold weather and create hazardous travel conditions.