https://www.mercurynews.com/2019/01/29/polar-vortex-what-it-is-and-why-people-are-freaking-out/

Jan 29 (Reuters) – A blast of arctic-chilled air brought dangerous, potentially record-setting cold to a wide swath of the United States on Tuesday, stretching from the Dakotas to Maine, with snow expected as far south as Alabama and Georgia.

Cities in the Midwest opened warming shelters as temperatures plummeted well below zero degrees Fahrenheit. Regional governments closed hundreds of schools and airlines canceled more than 1,000 flights, including those to Atlanta just days before the National Football League’s Super Bowl.