When a swirling mass of Arctic air descended on the U.S. ...
Lookups spiked on January 6, 2014.
A swirling mass of Arctic air, called a "polar vortex," descended on the U.S., bringing record cold and a blanket of media coverage.
For example, as the Washington Post explained, "The polar vortex that is chilling us this week is a band of low pressure Arctic air normally centered around the North Pole."
In general, a vortex is a mass of spinning air or liquid that pulls things into its center. Though this particular vortex involved cold air, we tend to associate vortexes (or vortices) with whirlpools. But its most common meaning is not its earliest: originally, the vortex referred to swirling fire or the swirling cosmos.
These days, the word is applied to a number of things that are frenetic swirls of activity: firestorms, dust devils, tornadoes, and hurricanes. Etymologically, that makes sense, since vortex stems ultimately from the Latin verb vertere, which means "to turn."