It's a term you hear every couple of winters, when we get stuck in the coldest of cold patterns – polar vortex. But what exactly is it?

A huge swath of the United States 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,

The National Weather Service said that wind chill temperatures could dip into the teens to low-20s from Texas across the Gulf Coast.

Thanks to the polar vortex, it feels like one, too. Why is it so cold? The Philadelphia region was hammered Monday by the season’s first big storm, with some areas in Delaware and the lower Jersey Shore collecting eight or more inches of snow.