NEW : The chill falls to -51 F in Rugby , North Dakota . Freezing an area at -20 F can be fun , but the bitter cold can be dangerous , too . One person is killed in Ohio accident that involved 86 vehicles . Wind chill watches and warnings are posted in parts of several states .
NEW : Wind chill falls to -51 F in Rugby , North Dakota . Freezing an egg at -20 F may be fun , but the bitter cold can be dangerous , too . One person is killed in Ohio accident that involved 86 vehicles . Wind chill advisories and warnings are posted in parts of 15 states .