Move over, haboob.
There's a new weather phenomenon in town, and it's largely responsible for the record-breaking cold that left most of the U.S. quite miserable Monday.
Twenty-six states were under wind-chill warnings or watches, with actual temperatures as low as 36-below zero reported in the Upper Midwest and wind chills as low as 60-below.
Meteorologists said a "polar vortex" was to blame.
Think of a polar vortex as a "polar cyclone," a great, swirling pool of extremely cold air located tens of thousands of feet in the atmosphere.
Though normally confined to the Arctic, this polar vortex is catching everyone's attention because it has dipped so low into North America — plunging millions of Americans and Canadians into a deep freeze.
NOAA scientists have suggested that climate change may be responsible for a weakening of the polar vortex.