The brutal polar air that has made the Midwest shiver over the past few days spread to the East and the Deep South on Tuesday, shattering records that in some cases had stood for more than a century.
The mercury plunged into the single digits and teens from Boston and New York to Atlanta, Birmingham, Nashville and Little Rock - places where many people don't know the first thing about extreme cold.
"I didn't think the South got this cold," said Marty Williams, a homeless man, originally from Chicago, who took shelter at a church in Atlanta, where it hit a record low of 6 degrees. "That was the main reason for me to come down from up North, from the cold, to get away from all that stuff."
The morning weather map for the eastern half of the U.S. looked like an algebra worksheet: lots of small, negative numbers. In fact, the Midwest and the East were colder than much of Antarctica.
The cold turned deadly for some: Authorities reported at least 21 cold-related deaths across the country since Sunday, including seven in Illinois, and six in Indiana. At least five people died after collapsing while shoveling snow, while several victims were identified as homeless people who either refused shelter or didn't make it to a warm haven soon enough to save themselves from the bitter temperatures.
In Missouri on Monday, a 1-year-old boy was killed when the car he was riding in struck a snow plow, and a 20-year-old woman was killed in a separate crash after her car slid on ice and into the path of a tractor-trailer.
In a phenomenon that forecasters said is actually not all that unusual, all 50 states saw freezing temperatures at some point Tuesday. That included Hawaii, where it was 18 degrees atop Mauna Kea, a dormant volcano.
The big chill started in the Midwest over the weekend, caused by a kink in the "polar vortex," the strong winds that circulate around the North Pole. By Tuesday, the icy air covered about half the country, and records were shattered like icicles up and down the Eastern Seaboard.
It was 1 degree in Reading, Pa., and 2 in Trenton, N.J. New York City plummeted to 4 degrees; the old record for the date was 6, set in 1896.
"It's brutal out here," said Spunkiy Jon, who took a break from her sanitation job in New York to smoke a cigarette in the cab of a garbage truck. "Your fingers freeze off after three minutes, your cheeks feel as if you're going to get windburn, and you work as quick as you can."
Farther south, Birmingham, Ala., dipped to a low of 7, four degrees colder than the old mark, set in 1970. Huntsville, Ala., dropped to 5, Nashville, Tenn., got down to 2, and Little Rock, Ark., fell to 9. Charlotte, N.C., reached 6 degrees, breaking the 12-degree record that had stood since 1884.
The deep freeze dragged on in the Midwest as well, with the thermometer reaching minus 12 overnight in the Chicago area and 14 below in suburban St. Louis. More than 500 Amtrak 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 worst should be over in the next day or two, when the polar vortex is expected to straighten itself out. Warmer weather - that is, near or above freezing - is in the forecast for much of the stricken part of the country.
On Tuesday, many schools and day care centers across the eastern half of the U.S. were closed so that youngsters wouldn't be exposed to the dangerous cold. Officials opened shelters for the homeless and anyone else who needed a warm place.
With the bitter cold slowing baggage handling and aircraft refueling, airlines canceled more than 2,000 flights in the U.S., bringing the four-day total to more than 11,000.
In New Orleans, which reported a low of 26 degrees, hardware stores ran out of pipe insulation. A pipe burst in an Atlanta suburb and a main road quickly froze over. In downtown Atlanta, a Ferris wheel near Centennial Olympic Park that opened over the summer to give riders a bird's eye view of the city closed because it was too cold.
Farther south in Pensacola, Fla., a Gulf Coast city better known for its white sand beaches than frost, streets normally filled with joggers, bikers and people walking dogs were deserted early Tuesday. A sign on a bank flashed 19 degrees. Patches of ice sparkled in parking lots where puddles froze overnight.
Monica Anderson and Tommy Howard jumped up and down and blew on their hands while they waited for a bus. Anderson said she couldn't recall it ever being so cold.
"I'm not used to it. It is best just to stay inside until it gets better," said Anderson, who had to get out for a doctor's appointment.
The Lower 48 states, when averaged out, reached a low of 13.8 degrees overnight Monday, according to calculations by Ryan Maue of Weather Bell Analytics. An estimated 190 million people in the U.S. were subjected to the polar vortex's icy blast.
Farmers worried about their crops.
Diane Cordeau of Kai-Kai Farm in Indiantown, Fla., about 90 miles north of Miami, had to pick her squash and tomatoes Monday to beat the freeze but said her leafy vegetables, such as kale, will be sweeter and tastier because of the cold.
"I'm the queen of lettuce around here, so the colder the better," said Cordeau, whose farm serves high-end restaurants that request specific produce or organic vegetables.
PJM Interconnection, which operates the power grid that serves more than 61 million people in t Mid-Atlantic, Midwest and South, asked users to conserve electricity because of the cold, especially in the morning and late afternoon.
Across the South, the Tennessee Valley Authority said power demand in the morning reached the second-highest winter peak in the history of the Depression-era utility. Temperatures averaged 4 degrees across the utility's seven-state region.
In South Carolina, a large utility used 15-minute rolling blackouts to handle demand, but there were no reports of widespread outages in the South.
Natural gas demand in the U.S. set a record Tuesday, eclipsing the mark set a day earlier, according to Jack Weixel, director of energy analysis at Bentek Energy.
In Chicago, it was too cold even for the polar bear at the Lincoln Park Zoo. While polar bears can handle below-zero cold in the wild, Anana was kept inside Monday because she doesn't have the thick layer of fat that bears typically develop from feeding on seals and whale carcasses.
Associated Press writers Steve Karnowski and Amy Forliti in Minneapolis; David Dishneau in Hagerstown, Md.; Brett Zongker in Washington, D.C.; Brett Barrouquere in Louisville, Ky.; Melissa Nelson-Gabriel in Pensacola, Fla.; Suzette Laboy in Indiantown, Fla.; Verena Donik in New York; and Kelly P. Kissel in Little Rock, Ark., contributed to this report.