Trooper Curtis Summerville with the Alabama State Patrol said the biggest problem on the roads was black ice on overpasses and bridges . About 100 flights at Chicago Midway International Airport canceled . Expected high in Bismarck , North Dakota , minus 11 , wind chill as low as minus 35 . At least 20 deaths attributed to deep freeze , which is reaching record lows in some areas . In Nashville , Tennessee , city officials turn on heat for those who ' n't pay utility bills .
About 100 flights at Chicago Midway International Airport canceled . Expected high in Bismarck , North Dakota , minus 11 , wind chill as low as minus 35 . At least 20 deaths attributed to deep freeze , which is reaching record lows in some areas . In Nashville , Tennessee , city officials turn on heat for those who ' n't pay utility bills .