At least eight people have died in the US Midwest as the region shivers in the grip of its worst cold snap in decades.
An Iowa student found dead outside a college building is among victims of the deadly freeze.
Hospitals have been treating patients reporting frostbite as life across a swathe of the nation grinds to a halt.
The iciest blasts may still come on Thursday. Ninety million people – a third of the US – have seen temperatures of -17 (0F) or below.
Some 250 million Americans overall have experienced the “polar vortex” conditions, but southern states such as Florida have escaped the brutal chill.
How did the fatalities occur?
- University of Iowa student Gerald Belz, 18, was found unresponsive behind a campus building before dawn on Wednesday and later died in hospital. Officials said weather was a factor
- A 70-year-old Michigan man was found dead near his home in Detroit, Michigan, on Wednesday. Officials said he was “inadequately dressed for the weather”
- Another Michigan man was also found frozen to death in his neighbourhood
- On Tuesday, a 55-year-old man froze to death in a garage in Milwaukee, Wisconsin, having “apparently collapsed after shovelling snow”, according to a medical examiner
- An 82-year-old in Pekin, Illinois, died from hypothermia just outside his home on Tuesday
- A 75-year-old man was fatally struck by a snow plough near Chicago on Monday. The driver has since been placed on paid leave pending an investigation, according to WGN9 News
- In northern Indiana, a young couple died after a collision on icy roads
What’s the forecast?
Thursday could see America’s third city of Chicago breaking its 1985 record low of -32C, according to meteorologists.
The chill is drifting eastward on Thursday, bringing sub-zero temperatures to Northeastern cities such as Boston.
Areas downwind of the Great Lakes are expected to be buried by intense lake-effect snow lakes into Thursday night.
The region near Buffalo, New York, should see the heaviest snowfall. Snow could fall at rates of 3in-5in (7cm-12cm) per hour.
The icy cold is expected to loosen its grip on Friday.
With wind chill factored in, the Midwest and Great Lakes have felt temperatures closer to -40C and -53C, which is enough to cause frostbite in under five minutes.
How is the cold snap affecting daily life?
In Minnesota, residents have been asked by natural gas company Xcel Energy to reduce their home thermostats to 17C in order to help the company handle heating demands.
Detroit, Michigan, has had over two dozen water mains freezing over this week. A city spokesman told the Associated Press the pipes were installed up to 1.8m below the frost line, but with such drastically low temperatures, the ground has still frozen through.
The US Postal Service has suspended all mail deliveries for the second day to parts of six states.
At least two people were critically injured in a 27-car pile-up on icy roads in Wyomissing, Pennsylvania.