A polar vortex swept over the Midwest on Monday, with temperatures dipping below 0 degrees Fahrenheit in Chicago, Detroit, St. Louis and other big cities.
![](http://darkroom.baltimoresun.com/a337e8b2/a5fe3427/RSSingBot%20(http://www.rssing.com).gif)
A polar vortex swept over the Midwest on Monday, with temperatures dipping below 0 degrees Fahrenheit in Chicago, Detroit, St. Louis and other big cities.