The polar vortex, a swirl of low-pressure air six miles up in the atmosphere, blasted much of the American Midwest and Northeast in late January 2019 with temperatures cold enough to bring on frostbite within minutes.
The polar vortex, a swirl of low-pressure air six miles up in the atmosphere, blasted much of the American Midwest and Northeast in late January 2019 with temperatures cold enough to bring on frostbite within minutes.