Arctic wind patterns create a sort of wall around the pole that prevents frigid air from trickling southward. That wall that keeps cold air contained is called polar vortex. Commonly, though, people refer to polar vortex when that retaining wall breaks or weakens and Arctic air slips out of the pole and into other regions.

The Upper Midwest and Northern Plains have been hit by Canada's freezing temperatures. On Thursday, Dec. 4, wind chills between negative 10 to negative 25 degrees will be expected, and the cold temperatures are expected to continue into Friday, Dec. 5 for those in the eastern U.S.

A polar vortex broke, and severe temperatures are set to dominate most of the United States, including the Midwest, in the coming days.

As we head into the polar vortex, meteorologists are calling for up to a foot of snow in some parts of the U.S.

A polar vortex will bring arctic air and subzero temperatures to parts of the U.S. through the middle of the month, according to AccuWeather. This first of three likely rounds will impact the U.S. starting this week,

As one blast of Arctic air pushes out to sea, already a new surge of cold air, driven by a breakdown of the polar vortex, is likely to expand from central Canada and through the midwestern and eastern United States.

Frigid Arctic air is pushing south into the United States, and fortunately, it doesn’t look like freezing temperatures will hit Texas just yet.

A strong polar vortex doesn't cause cold weather — it does the opposite. Here's what to know about polar vortices, how they work.

The phrase "polar vortex" has captured public attention and is now often misused to describe short-term bouts of frigid weather.