First, a helpful diagram from NOAA explaining how global warming has increased the Arctic Oscillation to give Chicago record-cold weather today:
Even though this concept is beyond the ken of some people, global warming increases weather extremes in both directions.
More Chiberia coverage:
Meanwhile, we've still got another 24 hours or so of this vortex to live through. The forecast right now predicts a high today of -26°C and low tonight of -29°C with wind-chill values down to -40°C.