Yes, it’s cold in Chicago — very cold — but does it qualify as a polar vortex?
The frosty term gained popularity back in 2014, when temperatures in Chicago hit -16 degrees Fahrenheit: a record low. It was so cold that Chicago Public Schools cancelled class over the temperature alone. (I still fondly remember those rare days off.)
But, according to Scott Lincoln, a senior hydrologist with the National Weather Service, the “polar vortex” isn’t really a thing. At least not how Chicagoans generally use the term.
So, What’s a Polar Vortex?
First, the polar vortex doesn’t come and go. It’s a circulation of air around Earth’s poles, and it’s always there, swirling 10 to 30 miles above us in the stratosphere.
The polar vortex is weaker in the summer and stronger in the winter. But sometimes, when polar vortex winds are not circling the pole as quickly, sections can move away from the pole. (Lincoln likened the typical movement to a flushing toilet bowl.) This allows the jet stream to move south, and we feel the cold air.
That’s what happened in 2014 and again in 2019, when lows plunged to 20 below zero.
However, Lincoln could not definitively say whether our current cold spell resulted from a disruption in the polar vortex. At least not yet. He’s more focused on how this cold is spreading across the country: aka the jet stream.
An illustration of a polar vortex event. (NOAA Climate.gov graphic, adapted from original by NOAA.gov.)
What About This Current Cold?
Chicago is experiencing an arctic air mass moving southeast from Canada. And we’re not the only ones: about two-thirds of the country is locked into this freezing pattern.
And while you might hear people (erroneously) referring to it as a polar vortex, overall, usage of the expression has waned.
As Lincoln explained, “You may have noticed that people are talking less about [the polar vortex] in recent years because the ‘buzz’ of the term has diminished since it became popular several years ago.”
A new phrase picking up steam appears to be “cold snap,” but that’s also not an official scientific term.
Then again, when you’re braving a 40-below wind chill, perhaps semantics isn’t exactly top of mind.
Stay warm, friends!
