'Polar vortex' chills Chicago to the bone

The brutal cold blast, known as the polar vortex, is a stream of air that spins around the stratosphere over the North Pole but whose current has been disrupted and is now pushing south into the United States.

The US Midwest region, including parts of Illinois, Indiana and Wisconsin and Michigan, was hit with record low temperatures that were forecast to last until Thursday.

It's not only the Midwest — the cold was expected to stretch from the Dakotas through Maine, with snow expected in Alabama and Georgia.

Illinois Governor J.B. Pritzker issued a disaster proclamation, offering resources to help officials respond.

"This storm poses a serious threat to the well-being of people around the state, and we will use every tool at our disposal to keep our residents safe," Pritzker said in a statement.

The Chicago public school system canceled all extracurricular activities on Tuesday and announced that all the schools in the 300,000-student system would be closed on Wednesday.