A deep freeze spread from the US Midwest to the East and South, setting record low temperatures from Boston to Birmingham, and leaving 21 people dead, authorities said.
The Midwest and the East experienced temperatures colder than much of Antarctica.
In a phenomenon that forecasters said is actually not all that unusual, all 50 states saw freezing temperatures at some point today. That included Hawaii, where it was -8 Celsius atop Mauna Kea, a dormant volcano.
The big chill started in the Midwest over the weekend, and by Tuesday, it covered about half of the country. In New York City, the high was expected to be -12 Celsius; in Boston, around -8 Celsius.
Across the South, records were shattered like icicles. Birmingham, Alabama, dipped to a low of -14 Celsius, breaking the record of -11.7 Celsius set in 1970.
Atlanta saw a record low of -14.5 Celsius. Nashville, Tennessee, got down to -16.7 Celsius, and Little Rock, Arkansas, fell to -13 Celsius. It was just -17 Celsius at Washington Dulles International airport, eclipsing the 1988 mark of -13 Celsius.
The deep freeze dragged on in the Midwest as well, with he thermometer reaching -24 Celsius overnight in the Chicago area and -25.5 Celsius in suburban St Louis.
More than 500 passengers were stranded overnight on three Chicago-bound trains that were stopped by blowing and drifting snow in Illinois. Food ran low, but the heat stayed on.
The cold turned deadly as authorities reported at least 21 cold-related deaths across the country since Sunday, including seven in Illinois, and six in Indiana.