https://phys.org/news/2019-01-record-breaking-cold-midwest-snowstorm.html

"You're talking about frostbite and hypothermia issues very quickly, like in a matter of minutes, maybe seconds," said Brian Hurley, a meteorologist with the Weather Prediction Center.

The cold also prompted officials to close some schools in eastern Iowa, while Chicago Public Schools officials said that Wednesday's classes have been canceled due to the anticipated cold snap.