If reading winter forecasts doesn't send a chill down your spine, stepping outside will.

In some regions of the country, temperatures are dropping below freezing, and some portions of the Midwest are experiencing temperatures below 40 degrees Fahrenheit and a mind-blowing wind chill of 75 degrees below zero thanks to the polar vortex. Accuweather predicts the Midwestern states will experience the extreme temperatures until later this week and cautions against stepping outside with any exposed skin. In these record-shattering temperatures, frostbite can occur after only a few minutes.

What is the polar vortex, the doomsday-sounding weather pattern blamed for these frigid conditions?

The term refers to a swirling mass of Arctic air that hovers around the north pole all year. Its swirling