The Myth, the Legend, the Polar Vortex
The polar vortex is coming! When you hear weather forecasters talk about winter’s blast of cold air you may have heard the term “polar vortex.” e term refers to unusually cold weather. But do you know what the polar vortex actually is?
The term polar vortex refers to cold air that is almost always circling around the earth’s poles. This air mass is usually associated with cold temperatures and winter weather. Normally, the polar vortex stays centered around the earth’s North and South Poles, at an altitude of roughly 10 miles up. e polar vortex usually stays there, kept in place by a circular current of air called a jet stream. When a low-pressure system is strong, the jet stream moves at high speeds (sometimes greater than 100 miles per hour), keeping the polar vortex in place. Sometimes, however, the low-pressure system and jet stream weaken, causing the cold air to drift away from the poles.
The polar vortex found above the North Pole is sometimes responsible for extremely cold weather here in the United States. When the low-pressure system weakens, the cold air contained in the polar vortex drifts southward, and we get to experience that cold arctic air for ourselves.
While the polar vortex has been happening for a long time, the term was only recently popularized. In January 2014, cold air from the northern polar vortex drifting southward, causing record lows in the United States. Even places as far south as Florida experienced Arctic air, and parts of Canada and the Midwestern United States had temperatures even colder than Alaska!
At the time, weather forecasters describing the phenomena popularized the term polar vortex. Cold air from the polar vortex has a ected the United States many times before that, notably in 1977, 1982, 1985, and 1989. ere was also another recent incident in December 2016, where temperatures dropped between 20 and 30 degrees below normal.
The United States isn’t the only place that can experience cold weather associated with the polar vortex. e polar vortex can also cause parts of Europe and Asia to experience Arctic air. Not all cold air is caused by the polar vortex, though.
What the polar vortex does cause is significant drops in temperature. When that happens, it’s important to bundle up. Wear at least three layers of clothes, a hat and gloves. Limit the time that you spent outside to prevent hypothermia. Check your local weather forecast on Weather.gov so you can know what to expect.
For more information about cold weather safety, visit:
National Oceanic and Atmospheric Administration
Weather.gov
