Roughly 40 million people from Texas to the Carolinas are under winter weather alerts, as a rare winter storm brings bone-chilling temperatures and potentially historic snowfall to cities unused to harsh cold weather.

"The level and extensiveness of the frigid air may be tough to match the rest of the winter," forecasters warned.

Heavy snow is expected to blanket large portions of the Eastern U.S. while much of the country will endure dangerously cold temperatures in the coming days

Major winter storm brings heavy snow to East Coast as Arctic blast puts millions under warnings from Plains to Maine