With two-thirds of the United States in the grip of a polar vortex, classes were canceled in Chicago, Minneapolis and other cities for two days as the mercury remained below zero in the Plains and across the Mideast.
Temperatures dipped to single digits from North Carolina to New York Tuesday but moderated Wednesday with afternoon readings reaching 16 F in Chicago and 21 F in New York City.
Record lows were set Tuesday in Atlanta, 6 F; Baltimore, 3 F and 4 F in Philadelphia, Accuweather.com said.
The cold was too much for Blue, a peacock at the Randall Oaks Barnyard Zoo in West Dundee, Ill., who died after escaping from the petting zoo in the arctic weather.
The bird was recaptured but died after being treated by a veterinarian, the Chicago Tribune reported.
Bundled-up schoolchildren returned to elementary, middle and high schools for the first time since Christmas break, but a CPS spokeswoman said they will have to make up missed days later in the school year, the Chicago Sun-Times reported.
"It's been crazy -- just keeping the kids busy," a harried parent dropping off her two young children at McPherson Elementary School told the newspaper. "They've been bouncing off the walls. They need to go back to school."
Authorities in Lakeville, Minn., said an autopsy would be conducted to determine the cause of death of a 32-year-old woman found on the doorstep of her family's home in sub-zero weather Tuesday afternoon. The front door was locked but the woman had house keys in her hand.
"Police are not sure if the extreme cold played a role in the death but observed evidence of possible hypothermia before death," police said in a news release. The (Minneapolis) Star Tribune said the woman may have froze to death.
"It's still going to be below average for most of the East but the worst of the Arctic outbreak is over with," said Guy Walton, a meteorologist at The Weather Channel. "It will be getting dramatically warmer from today. It is still as much as 20 degrees below average in the Northeast but by Thursday temperatures will be almost back to normal."
AccuWeather.com forecaster Paul Pastelok predicted fairly normal wintertime temperatures until the next cold wave dips into the Plains around Jan. 18 and moves east.
Notable deaths of 2014 [PHOTOS]