An icy polar blast brought dangerously low temperatures to the US Midwest, with a freeze normally reserved for the Antarctica as temperatures dropped to nearly 45 degrees Celsius below zero.
The frightful cold, expected to bottom out with record lows Thursday morning (local time), was blamed for several deaths across the region, and fears for the most vulnerable populations soared as night fell.
The nearly unthinkable temperatures caused airline gas lines to freeze and electrical grids to collapse, and they kept much of the northern United States homebound.
Power outages roiled swaths of Wisconsin and Iowa, plunging thousands into a brief, unheated darkness. The dry, frigid air froze exposed water instantly, led to spontaneous nosebleeds, and made even brief forays outdoors extremely hazardous.
Officials in Michigan, Wisconsin and Minnesota had linked at least six deaths to the weather, including several people who probably froze to death. Governors in Wisconsin and Michigan declared states of emergency and ordered all state government offices closed; some state agencies in Illinois were closed Wednesday, as well.
AP- Ice covers the Chicago River as record-breaking temperatures triggered widespread closures of schools and businesses.
The capitol building where people sought shelter during business hours, remained open as the temperatures outside plunged to minus-31C; the estimated wind chill made it feel like minus-44 degrees C.
It was colder than Alaska's North Slope in many places, including Norris Camp, Minnesota, where temperatures dropped to minus-44 degrees C Wednesday morning - with the wind chill pegged at minus-53C - making the town the coldest reporting location in the United States and one of the coldest spots on Earth.
Even Hell, Michigan, froze over. The community outside of Ann Arbor was expected to see temperatures drop to minus-32C overnight into Thursday. The nearby University of Michigan took the rare step of cancelling classes through Thursday.
AP- Bundled-up Chicagoans try to deal with a deadly arctic deep freeze that enveloped the US Midwest with record-breaking temperatures.
From Minnesota to Michigan, the polar vortex brought with it a slew of school closures, mail service interruptions and more than 1000 airline flight cancellations. Scores of restaurants, grocery stores and coffee shops shuttered for the day or shortened business hours.
Streets in Chicago were nearly empty, with few people walking outside in the painfully cold air as temperatures hovered around minus 28 Celsius.
For the region's most vulnerable - even those hardened to the Upper Midwest's long winters - this polar vortex has been especially perilous.
Karen Andro, director of Hope's Home Ministries at the First United Methodist Church in Madison, has spent much of the past few days coordinating with other nonprofits and government agencies to arrange transportation, hot meals and warming centres for the city's homeless residents.
"The cold exacerbates everything," Andro said, noting that homeless people with mental illness, disabilities and health problems are at extreme risk.
Even some Midwestern homes were not cold-proofed refuges for hardened residents.
AP- Icicles form on a railing along the Chicago lakefront from North Avenue beach on a frigid morning.
Brian Wallheimer, a university science writer, corralled his three young children at home in Rockford, Illinois, after schools closed their doors. The freezing air infiltrated his-two story home northwest of Chicago, he said, and frost has accumulated on the window sills and door hinges.
"I've never seen that happen," Wallheimer, 39, said, as his children - 9, 6 and 4 years old - hatched plans to build a blanket fort in the basement.
Classes were cancelled for Wednesday and Thursday for students across the Midwest, including Chicago, home of the nation's third-largest school system, and police warned of the heightened risk of accidents on icy highways.
Residents closed their curtains to keep cold air from leaking in around window panes and opened cabinet doors to prevent pipes from freezing.
Most electricity outages were resolved in a matter of hours.
"I was amazed how fast they got it back," said Dan Bark, whose house sits diagonally across from damaged power lines. "We were trying to figure out contingency plans."
He pondered taking his family and cats to his mother's home nearby. Bark has a generator, but it was in the garage - and frozen. He conceded that was not ideal, but he also had never seen the temperatures dip quite so low.
"This is the coldest it's ever been," Bark said.
