But we're still getting asked this question: Just what is the polar vortex, and why is it bringing super-cold temperatures to so much of the U.S.? So here's another go at it.

The polar vortex not only annoyed the millions it blasted with bitter cold in 2014, but also language purists who cringed at the way it was used.

At right: A strong phase of the polar vortex in mid-November 2013. Dark purple depicts the most frigid air tightly contained in an oval-shaped formation. The light purple line forming the ...

To guard against overuse of the term, we should reserve calling special attention to the vortex to those cases in which its behavior is extreme.

Though most of the United States still shivers with memories of the polar vortex, 2014 was actually the warmest year on record according to separate analyses by the National Oceanic and ...

During the Polar Vortex, much of the country faced extreme cold of the kind it hadn’t experienced for years, with the average temperature on Jan. 6, 2014 – the height of the event – sinking ...

You’ve probably heard the term “polar vortex” a lot today. From the Midwest to the Northeast to as far south as Alabama, forecasters and scientists have been blaming the nation’s current ...

What some people are calling the polar vortex, last winter's favorite whipping boy, will make a rare summer cameo in the central U.S. next week in what's typically one of the hottest weeks of the ...

Meteorologists are annoyed by the hype around the phrase "polar vortex." This week's frigid snap, they say, was just a regular old cold front.

A blast of brutally cold air - thanks to the polar vortex - is roaring across the central and eastern USA early this week, sending temperatures to levels not seen in 20 years. The polar vortex is ...

Polar vortex killed at least 21 By Associated Press Published Jan. 8, 2014, 6:54 a.m. ET Paul Martinka ...