Marius Radoi keeps his balance as he walks on the edge of Lake Michigan's shore line as temperatures dropped to -20 degrees F (-29C) on January 30, 2019 in Chicago, Illinois. - Frostbite warnings were issued for parts of the US Midwest on January 30, 2019, as temperatures colder than Antarctica grounded flights, forced schools and businesses to close and disrupted life for tens of millions. (Photo by JOSHUA LOTT / AFP)