Meteorologists warn that a stretched polar vortex could bring severe winter weather to much of the United States.

Rising Arctic temperatures and melting sea ice could be causing cold air to flow into the Northern Hemisphere. But not all scientists agree.

As the U.S. prepares to take on another bout of cold weather, the term "polar vortex" is getting thrown around. But what is it?

Much of the nation east of the Rocky Mountains is hunkered down for what could be the worst winter storm of the season.

Despite being notorious for bringing brutal cold and dangerous wind chills, the polar vortex has a surprising upside. Discover how it can lead to clearer skies, fewer storms, and ideal conditions for winter activities.

Behind the historic winter storm that blasted 40 states this weekend, a dome of Arctic air associated with the polar vortex will bring days of life-threatening temperatures to much of the country, refreezing ice and snow,

The meteorologists said the polar vortex system is set up due north of Michigan over Canada's Hudson Bay. It's at least partly responsible for the frigid temperatures around the region that contributed this week to a 100-vehicle pileup in southwest Michigan and led the city of Detroit to declare a cold weather health emergency.

Temperatures could fall below -20 F across certain parts of North Dakota and Minnesota.

More snow is on the way for southern Ontario, with a widespread shot occurring on Wednesday. That will be followed by bitterly cold temperatures and wind chills late week