The polar air that has made the Midwestern United States shiver over the past few days spread to the East and South, setting record low temperatures from Boston and New York to Atlanta, Birmingham and Nashville.

The Midwest and the East were colder on Tuesday 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 on Tuesday. 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.

The deep freeze dragged on in the Midwest as well, with the thermometer reaching minus -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.

Cold turns deadly

Authorities reported at least 21 cold-related deaths across the country since Sunday

The worst should be over in the next day or two. Warmer weather at least, near or above freezing is in the forecast for much of the stricken part of the country.

On Tuesday, many schools and day care centres across the eastern half of the US were closed. Officials opened shelters for the homeless and anyone else who needed a warm place.

With the bitter cold slowing baggage handling and aircraft refuelling, airlines cancelled more than 2,000 flights in the US, bringing the four-day total to more than 11,000.

An estimated 190 million people in the US were subjected to the icy blast, caused by a kink in the “polar vortex,” the strong winds that surround the North Pole.

In Chicago, it was too cold even for the polar bear at the Lincoln Park Zoo. While polar bears can handle below freezing cold in the wild, Anana was kept inside on Monday because she doesn’t have the thick layer of fat that bears typically get from feeding on seals and whale carcasses.

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