WASHINGTON — The polar vortex dumped snow and cold Arctic air on parts of the northeast United States and Canada over Mother's Day weekend, the Associated Press reports.
According to the National Oceanic and Atmospheric Administration, the polar vortex is a band of low pressure Arctic air normally centered around the North Pole. It is located in the middle and upper tropospheres and extends into the stratosphere.
The polar vortex is usually held in place by a current called the jet stream. Disturbances in the jet stream can push frigid, wintry air to parts of Canada and the U.S., while high-pressure systems of warmer air bulge northwards elsewhere.
