The shores of Lake Michigan near Montrose Beach in Chicago was a sea of white after a blast of Arctic air from the polar vortex brought dangerous, bone-chilling cold to a wide swathe of the United States on Tuesday.
The Midwest was the hardest-hit by the sub-zero temperatures, which the authorities say could be life-threatening.
The mercury fell to as low as minus 18 deg C in Chicago, while the temperatures tumbled to a frigid minus 29 deg C in Minneapolis. As much as 60cm of snow was forecast in Wisconsin.
Parts of the Chicago River and Lake Michigan were filled with chunks of ice as a result of the brutal cold.
Many cities in the Midwest have opened warming shelters for the tens of millions of people who will be affected.