Here's everything you need to know about a common cause of frigid weather.
Does the thought of being blasted by Arctic air send shivers down your spine? Well, bundle up — because the dreaded polar vortex can quickly make winter weather even colder than usual.
Here's more about what the polar vortex is — and what it's most definitely not.
What is the polar vortex?
The polar vortex is an area of low pressure and cold air that swirls like a wheel around each of Earth's two polar regions. Sometimes the Arctic polar vortex wobbles and a lobe surges south, blanketing parts of North America with bitter temperatures.
The polar vortex lives high in the atmosphere and doesn't bring snow or ice with it, according to NBC News meteorologist Sherri Pugh.
"It's actually in the stratosphere," Pugh said. "Our weather happens in the lower level of the atmosphere, and this occurs just right above that lower level."
Is the polar vortex a new phenomenon?
While the record-breaking cold of January 2014 may have been the first time you heard about the polar vortex, the phenomenon has been around forever. According to Weather Channel senior meteorologist Stu Ostro, the term was used even before the Civil War.
And the polar vortex exists even when you don't feel its effects.
"The polar vortex doesn't come and go," Pugh said. "It does weaken and strengthen, and that's how it fuels the weather around the world."
How low do temperatures go?
"It depends. While you're dealing with subzero temperatures at the pole, it does modify, fortunately, as it comes further south," Pugh said.
But with the wind chill, temperatures can feel significantly more punishing.
"If you add just a little bit of wind, it can really make it feel so much more brutally cold," Pugh said. "It doesn't take a lot of wind once we get so cold for it to feel even worse. So while the temperatures are cold enough to begin with, you can add a little wind chill to make it absolutely bitter."
Is America the only place that experiences effects of the polar vortex?
Hardly. The chill we feel passes through Canada first. And the polar vortex delivers cold air to Europe and Siberia, plus other parts of Asia, too.
Is the polar vortex tied to climate change?
The polar vortex is separate from global warming and climate change.
"Climate change is not based on a single event like a polar vortex-induced cold snap," TODAY's Al Roker said. "It's measured over a long period of time and government statistics, going back to 1880 when record-keeping began, show that on average, the world's annual temperature has been ticking upward."
Climate change also hasn't affected the frequency of how often we experience the polar vortex or the temperatures associated with it, Pugh said.
"While some [other weather] events are signatures of a warming planet, this is not one of those events, and we do not give attribution to climate changes for the swings in the polar vortex," she said. "It's been a phenomenon that has been studied for decades now."
Stay warm during the polar vortex with these tips for avoiding frostbite and hypothermia from the National Weather Service.
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