What is the polar vortex? In-depth look at how it can affect winter weather in the US.

·3 min read

The polar vortex has only recently entered the popular lexicon as something to fear or shiver at each winter: But what is it? Is it a storm that's heading south from the Arctic or perhaps a new climate pattern to worry about, like El Niño? No to both, scientists say.

The polar vortex – everyone's favorite wintertime whipping boy – is actually a gigantic, circular area of cold air high up in the atmosphere that typically spins over the North Pole (as its name suggests). It's a normal pattern that's stronger in the winter and usually tends to keep the coldest weather bottled up near the North Pole.

When the polar vortex is "strong," cold air is less likely to plunge deep into North America, Weather.com meteorologist Jonathan Erdman said. The stronger the polar vortex, the milder the USA's winter is.

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But occasionally, some of the vortex can break off or move south, funneling unspeakably cold temperatures down south into the U.S., Europe and Asia.

When the polar vortex weakens or even splits, it allows frigid air to escape and push southward toward the USA.

A commuter makes a sub-zero trek through Chicago on Jan. 6, 2014. That cold snap was due in part to the polar vortex.
A commuter makes a sub-zero trek through Chicago on Jan. 6, 2014. That cold snap was due in part to the polar vortex.

How the position of the vortex determines where it's frigid

The vortex is strongest during the winter and usually weakens or even disappears in the summer. Its position can determine what part of the U.S. the Arctic air will invade.

It can divide into several parts, then get back together again, like the cop in "Terminator 2."

And it's not exactly a new phenomenon, either, despite how hashtag-friendly it is.

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The vortex has likely "existed in some form for the past 4.5 billion years," according to senior scientist Jeff Kiehl of the National Center for Atmospheric Research in Boulder, Colorado.

In fact, it's thought that the term "polar vortex" first appeared in an 1853 issue of the magazine Littell's Living Age, the National Oceanic and Atmospheric Administration said.

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And although it's been understood by scientists for several decades, it only entered the popular lexicon as a synonym for miserably cold winter weather a few years ago.

The polar vortex may be connected to global warming recently

One caveat: Scientists report that the polar vortex has been wandering more often in recent years.

Some scientists said there may be a connection between global warming and the wandering vortex: The theory is that when weird warmth invades the Arctic, some of the cold that's supposed to stay up there – including the vortex – instead sloshes down south into North America and Europe.

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In any event, don't fear the polar vortex. It isn't like a tornado or hurricane; it's not something you can look up and see in the sky one day; there's no freakish spinning whirlwind of ice and snow roaring down from Canada.

When or if it arrives, it will just be very cold, which is also known as ... winter.


This article originally appeared on USA TODAY: Polar vortex 2022: What is it and how does it affect winter weather

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