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 freezing temperatures on a “polar vortex,” a whirlpool of dense, frigid air all the way from the North Pole.
The vortex brought tundra-like winter to the Midwest and Northeast on Sunday. Temperatures fell well below zero in Indiana, North Dakota, Minnesota and other states. By Monday, the region was battling the more cold temperatures in addition to lots of snow.
As it turns out, a polar vortex isn't just a term coined my meteorologists — it's a real weather occurrence.
NASA explains that polar vortexes forms in the stratosphere, and they feature winds that spin counterclockwise above the pole.
This pattern is very similar to that of a hurricane — think of a polar vortex as a snowy, Arctic version of its tropical counterpart.
But this isn't the first time the world's seen a polar vortex. Polar vortexes are a seasonal occurrence and form every winter over the Arctic, according to the National Oceanic and Atmospheric Administration.
Normally, vortexes are confined to the polar region, NOAA explains. However, when a vortex's wind rings break down, cold air can spill out, blasting the U.S. with chilly conditions. A 2009-2010 vortex breakdown contributed to that winter's massive snowstorms.
NOAA scientists suggest that warmer conditions in the Arctic would weaken the vortex and push frigid winds south.
Forecasts show temperatures around the country will begin moderating by the end of the week, NBC News reports.
Of course, it's hard to predict if we'll see another vortex before the winter's end.