Weather security

Polar vortex returns: Here’s where it’ll be coldest

Extreme cold is moving across more of the country this week, bringing with it the potential for record lows and dangerous conditions for children, pets and anyone else without adequate protection — all thanks to a weather phenomenon known as the polar vortex.

What is the polar vortex?

This phrase is once again in the headlines, and worth re-defining. The “polar vortex” technically refers to a large area of low pressure and cold air that surrounds both of the Earth’s poles, according to the National Weather Service. It’s always existed at the poles, but the polar vortex strengthens in particular during the winter and can send cold air southward. 

Temperatures dip to dangerous lows when the polar vortex expands, sending thermometers plummeting.

There have been a number of notable cold snaps caused by the polar vortex, including in 1977, 1982, 1985, 1989 and 2014, according to the weather service.