The National Weather Service says overnight lows reached the minus 20s and lower across much of the northern Plains on Sunday morning as a fresh surge of bitter arctic air reached into the Midwest.
Weather-related delays at Indianapolis International Airport caused about 100 passengers to spend the night in the terminal, but most travelers were on their way Sunday morning.
In southwestern Michigan, icy conditions appear to have played a role in a crash that killed a 73-year-old motorist.
Chicago police say a commercial plane slid off a runway early Sunday at O'Hare International Airport.
