Winter winds brought extreme cold and ice-slicked roads to the mid-western and eastern United States yesterday, with the Martin Luther King Jr Day holiday and an ongoing government shutdown allowing many to heed official advice to stay indoors.
The arctic blast of frigid air has followed a January storm that dumped more than a foot (30cm) of snow and sleet across the northeast, which started melting on Sunday.
In a Chicago suburb, a 12-year-old girl died after a snow fort she had built after church on Sunday collapsed on her, according to the Arlington Heights Police Department.
A nine-year-old girl she was playing with was treated for hypothermia after being dug out of the snow and is expected to survive, police said.
Authorities said an autopsy is scheduled for the 12-year-old, who was pronounced dead about 4.30pm (2230 GMT on Sunday) at Northwest Community Hospital.
The girls were at church with their families and went outside to play, police said.
When an hour had passed and the girls hadn’t returned, the families went outside to look for them and found them buried in the snow.
Relatives and church members had pulled the girls out of the snow by the time police and fire crews arrived about 2.40pm, Sergeant Charles Buczynski said.
“It’s just a tragic accident,” he added.
It’s not clear how long the girls were trapped in the snow, Buczynski said.
No one witnessed the collapse, he said.
It was about -10° Celsius in Arlington Heights while the girls were outside, according to the National Weather Service (NWS).
Temperatures fell to single-digits Fahrenheit (about -20°C) from New York City to Boston and through northern New England, and froze melting snow late on Sunday and early yesterday, said Marc Chenard at the NWS’s Weather Prediction Centre in College Park, Maryland.
Winds up to 30mph to 40mph (48-64kph) added possibly deadly wind chill.
“This is definitely dangerous, life-and-death kind of weather happening,” Chenard said. “Minnesota and Wisconsin will see temperatures in the negative 20s.”
“Boston will be just three degrees (Fahrenheit) this morning, with wind chills of -12 or more,” he said. “New York City and DC will be in that same range, maybe hitting the teens later today. 
“It’ll be record or near-record cold.”
The NWS issued wind-chill advisories and warnings for more than 10 states, from North Dakota and to East Coast metropolitan centres.
High temperatures yesterday were forecast at 17° Fahrenheit (-8°C) for New York City and 12°F (-11°C) for Boston.
Many Americans had the day off work yesterday, either because of the holiday or because they are among the furloughed federal government workers who find themselves in the longest shutdown in US history, caused by an impasse over funding US President Donald Trump’s plans to build more barriers on the US-Mexico border.
More than 7,500 flights were delayed, mostly in New York and New England, according to FlightAware.com, down from more than 14,000 on Sunday.
Today’s weather will be only slightly warmer, the NWS’s Chenard said, with temperatures reaching the low 20s Fahrenheit in the Northeast.
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