Officials warned of near-instant frostbite as temperatures in the region fell below zero on Wednesday. Some state offices are closed and postal workers do not deliver mail in 10 states. Thousands of flights were canceled along with dozens of train services – most of them inside and outside Chicago.
About 212 million people – or 72% of the continental US population – will fall under frost in the coming days. And more than 83 million Americans – about 25% of the US population – will eventually fall below zero degrees Celsius between Wednesday and Monday.
At least five deaths due to the extreme conditions this week are the authorities are calling on people to gather, stay inside and find out about the elderly and vulnerable, called by experts as "the coldest air of a generation be designated.
While most of the Midwest will have freezing temperatures, Chicago will be "the epicenter" of the extreme cold, "said CNN meteorologist Dave Hennen.
Chicago reached a record low of 27 below zero on Thursday morning. Wednesday's high is forecast to be below zero on Wednesday.
The National Weather Service in Chicago tweeted on Tuesday night, with temperatures already falling.
"Chicago officially dropped below zero before 6 am on O & # 39; Hare and may not return to zero by Thursday night, it said.
It's going to be so cold that Chicago's residents feel better in parts Antarctic Priestley Glacier on Wednesday has a high temperature of 6 degrees Fahrenheit and a low of 7 below zero.  More than 2,700 flights to US airports will be canceled on Tuesday and Wednesday, including around 1,550 in and out of Chicago airports, according to FlightAware.com.
Amtrak also canceled all trains to and from Chicago on Wednesday due to weather conditions, including short and night trains. It said it normally operates 55 trains daily to and from Chicago Hub.
Mail delivery is also canceled in Illinois, Iowa, Minnesota, North Dakota, South Dakota, Wisconsin and parts of Kansas, Missouri, Montana and Nebraska.
In Minnesota, frostbite can occur in minutes.
Frigid temperatures are not the only concern. In Minnesota, stormy weather could mean that the wind shower is approaching negative 70. In Ponsford, the wind shower was negative 66, said the CNN meteorologist Michael Guy.
"These are very dangerous conditions that can lead to frostbite in exposed skin in less than five minutes when wind temperatures are below -50," tweeted the National Weather Service. "The best thing you can do is limit your time outside."
Hens described it as "the coldest air in a generation." Temperatures will drop to between 20 and 40 degrees below zero between Tuesday and Thursday in the upper Midwest, Hens said. In the north of Minnesota, wind temperatures were forecast to drop to between 65 and 70 degrees, which in 1982 could compete with the coldest windfall ever recorded in the state (71).
Frostbite is also an issue in Central Iowa.
Wind chill in central Iowa is also a major concern.
The National Weather Service predicted negative 45 degrees of negative wind for Des Moines, negative 57 for Waterloo and negative 60 for Mason City on Wednesday night.
"This is the coldest air many of us have ever experienced," she tweeted.
Wind Chill refers to how cold people and animals feel when they are outside, according to the weather service. It's how much heat is lost from exposed skin while it's windy and cold. The faster the wind is, the more heat is removed from the body, which lowers the skin temperature and ultimately the body temperature.
Frostbite is caused by freezing of the skin and underlying tissues. It is most common on the fingers, toes, nose, ears, cheeks and chin. Heavy cases can kill body tissues.
Inhabitants of North Dakota Should Avoid Streets
In North Dakota, the authorities issued a "no-travel" rating to the northeastern region of the state, warning motorists in these areas for visibility to start from zero snow. The region includes Grand Forks and the surrounding areas.
The North Dakota Highway Patrol said it also issued a travel alarm because of the snowdrift in southeastern North Dakota. Destinations included in the travel warning are Fargo, Casselton and its surroundings.
"A travel warning means that motorists can still be traveling in these areas, but they should be alerted to changing conditions – motorists should wear safety belts, reduce speed and ride according to conditions," it said.
The wind shower at Grand Forks International Airport was 61 degrees below zero, the National Weather Service said. The extreme cold will continue on Thursday and the wind will be shut down until the late 1960s, according to the National Weather Service.
Michigan State Offices Closed
In western Michigan, with wind chill between minus 20 and minus 40 expected from Wednesday through Thursday morning, the National Weather Service warned residents against the temperatures that hit Following these days is nothing to start with. "
" We are not used to it. Take steps to prevent frostbite and hypothermia, "it said.
All state offices are closed on Wednesday and Michigan Gov. Gretchen Whitmer has declared a state of emergency.
" Such widespread, extreme conditions have been around in Michigan not occurred for many years. Low temperatures are predicted by the National Meteorological Service, "she said.
" In many places, wind cold is predicted to be up to 50 degrees below zero, for example, in the Detroit metro, which is unaccustomed to these temperatures.
Brutal weather Deaths
The cold temperatures, at least five deaths have been associated with the extreme weather this week.
And Illinois died Man on Monday in an accident with a village plow car and a pedestrian, said the police of Libertyville.The driver of the plow wagon was in egg until the result of the investigation paid administrative leave. The same day, Ethan and Shawna Kiser were killed as their Saturn Vue turned sideways and into the path of a GMC yukon in northern Indiana, authorities said. The couple were 22 and 21 years old.
A 55-year-old man was found dead in the free-standing garage of his Milwaukee home Tuesday after apparently collapsing while snow shoveling, the coroner's office said.
Joe Sutton and Dave Alsup of CNN contributed to this report.