Apologies to anyone trying to fly out of Chicago.

The bitter polar vortex caused hordes of flights to be canceled across the country on Wednesday, with almost 2,000 flights canceled at Chicago's O'Hare and Midway airports alone.

In total, with a mass of extremely cold air freezing out the Midwest and Northeast, 3,576 flights were canceled.

As Amtrak suspended service into and out of Chicago, fuel lines at O’Hare Airport froze, forcing some planes to refuel elsewhere before continuing to their destination, an airport spokeswoman told the Associated Press.

American Airlines confirmed to USA TODAY they experienced issues refueling in the extreme temperatures.

Extreme weather: Polar vortex in Midwest, record heat in Australia, odd warmth in Alaska. What's going on?

"In (an) attempt to operate as many flights as possible and accommodate as many customers as possible, some flights are being sent in with an overage of fuel to get to their next destination without needing to take on fuel at ORD, and others are departing ORD and making a fuel stop before they reach their final destination," American Airlines spokesman Ross Feinstein said in a statement.

The temperature reached minus 23 at O’Hare International Airport, with a wind chill of 52 degrees below zero, according to the National Weather Service.

Another 2,159 flights nationwide scheduled for Thursday have also been called off, according to flight tracker FlightAware.

This article originally appeared on USA TODAY: Polar vortex causes another lousy travel day for fliers </s> CHICAGO – An historic and deadly polar vortex gripped a wide swath of the nation Wednesday, with temperatures plunging far below zero and wind chill numbers as extraordinary as they are dangerous.

Chicago's temperature tumbled to 21 degrees below zero, a record for the date and closing in on the city's all-time record of minus 27 set in 1985. The wind chill dipped to an even more startling 51 degrees below zero.

The National Weather Service said the temperature reached minus 28 degrees in Minneapolis, poised to break a record dating back more than 100 years. The wind chill: minus 49.

Wind chill temperatures in dozens of towns across Minnesota and North Dakota plummeted to 60 degrees below zero or less, the National Weather Service said. The early leader was Ponsford, Minnesota, with a very cool minus 66 degrees.

Frostbite can set in within five minutes in such temperatures, the weather service said.

"One of the coldest arctic air mass intrusions in recent memory is surging south into the Upper Midwest before spreading across much of the eastern two-thirds of the country," the National Weather Service said, warning of "life-threatening wind chills, likely leading to widespread record lows and low maximum temperatures."

Even the Postal Service took notice, announcing that due to concerns for the safety of its employees, mail won't be delivered Wednesday in parts of at least 10 states. More than 1,000 flights were canceled or delayed across the region, with Chicago's O'Hare suffering the most chaos.

Amtrak pulled the plug in Chicago, announcing the "extreme weather conditions and an abundance of caution" led the service to cancel all trains to and from the city on Wednesday. Short-distance services are also canceled on Thursday, Amtrak said.

Light rail was also a mess, with some suburban lines shutting down Wednesday. The Chicago Transit Authority, which shuttles about 1.6 million riders on a typical weekday, said it was experiencing significant delays.

At least four deaths were linked to the weather system, including a man struck and killed by a snow plow in the Chicago area, a young couple whose SUV struck another on a snowy road in northern Indiana and a Milwaukee man found frozen to death in a garage.

Chicago River freezing: Here's what it looks like in sub-zero temperatures

Homeless shelters and warming centers were abuzz across the region. In Chicago, officials added 500 shelter beds and tapped more than 100 religious leaders to make calls and checks on senior citizens. Five Chicago Transit Authority buses were dispatched to give homeless people a place to warm up who might not want to go to a shelter.

“Everyone of us has a role to check on somebody who is maybe a neighbor on the block who is elderly, infirm or needs extra help,” Mayor Rahm Emanuel said.

"Don't leave your pets outside unattended in this weather, period," the rescue organization warned on Twitter. "Make sure your gates are latched and your dog(s) cannot escape your yard."

The weekend could finally bring relief. In Des Moines, Iowa, the temperature barreled down to minus 20 on Wednesday with a wind chill of minus 40. But Allan Curtis, a meteorologist with the Des Moines branch of the National Weather Service, said the temperature on Saturday could exceed 40 degrees above zero.

“It may as well be basketball shorts weather,” Curtis said.

Madhani reported from Chicago, Bacon from McLean, Virgina. Contributing: Austin Cannon, Des Moines Register; The Associated Press

Extreme cold: How long does it take for hypothermia, mummified skin to set in

This article originally appeared on USA TODAY: It feels like 51 below zero in Chicago: Polar vortex strikes Midwest </s> BISMARCK, N.D. -- A deadly arctic deep freeze enveloped the Midwest with record-breaking temperatures on Wednesday, triggering widespread closures of schools and businesses, and the cancelling of more than 1,500 flights from Chicago's airports. The cold even prompted the U.S. Postal Service to suspend mail delivery to a wide swath of the region.

Many normal activities shut down and residents huddled inside as the National Weather Service forecast plunging temperatures from one of the coldest air masses in years. The bitter cold is the result of a split in the polar vortex that allowed temperatures to drop much farther south than normal.

In Chicago, temperatures were still dropping after plunging early Wednesday to minus 19 degrees (negative 28 Celsius), breaking the day's previous record low set in 1966. Snowplows were idled overnight in southwestern Minnesota, where temperatures dropped to negative 29 degrees (negative 34 Celsius). And the temperature in Fargo, North Dakota, was 31 degrees below zero (negative 35 Celsius).

In addition to the flight cancellations in Chicago at O'Hare International Airport and Midway International Airport, the extreme cold prompted Amtrak to cancel all trains into and out of Chicago.

Officials throughout the region were focused on protecting vulnerable people from the cold , including the homeless, seniors and those living in substandard housing. Some buses were turned into mobile warming shelters to help the homeless in Chicago.

Governors in Illinois, Wisconsin and Michigan declared emergencies as the worst of the cold threatened on Wednesday. In Chicago, major attractions closed because of the bitter cold, including the Lincoln Park Zoo, the Art Institute and the Field Museum.

“These (conditions) are actually a public health risk and you need to treat it appropriately,” Chicago Mayor Rahm Emanuel said Tuesday. “They are life-threatening conditions and temperatures.”

A wind chill of minus 25 (negative 32 degrees Celsius) can freeze skin within 15 minutes, according to the National Weather Service.

In Michigan, homeless shelters in Lansing were becoming “overloaded,” Mayor Andy Schor said. They also were filling up in Detroit.

“People don't want to be out there right now,” said Brennan Ellis, 53, who is staying at the Detroit Rescue Mission Ministries.

Detroit's outlook was for Wednesday overnight lows around minus 12 (negative 24 degrees Celsius), with wind chills dropping to minus 35 (negative 37 degrees Celsius).

At least four deaths were linked to the weather system Tuesday, including a man struck and killed by a snow plow in the Chicago area, a young couple whose SUV struck another on a snowy road in northern Indiana and a Milwaukee man found frozen to death in a garage.

A popular saying goes: “Neither snow nor rain nor heat ...” will stop the mail from being delivered. But extreme cold will on Wednesday.

The U.S. Postal Service said it would suspend mail delivery on Wednesday in parts or all of several Midwest states including North Dakota, South Dakota, Nebraska, Kansas, Minnesota, Wisconsin, Iowa, Illinois, Indiana and Michigan.

Hawaii native Charles Henry, 54, was staying at a shelter in St. Paul, Minnesota, and said he was grateful to have a place to stay out of the cold.

“That wind chill out there is not even a joke,” he said. “I feel sorry for anybody that has to stay outside.”

Chicago was turning five buses into makeshift warming centres moving around the city, some with nurses aboard, to encourage the homeless to come in from the cold.

“We're bringing the warming shelters to them, so they can stay near all of their stuff and still warm up,” said Cristina Villarreal, spokeswoman for the city's Department of Family and Support Services.

Shelters, churches and city departments in Detroit worked together to help get vulnerable people out of the cold, offering the message to those who refused help that “you're going to freeze or lose a limb,” said Terra DeFoe, a senior adviser to Detroit Mayor Mike Duggan.

Hundreds of public schools and several large universities from North Dakota to Pennsylvania cancelled classes Tuesday or planned to do so Wednesday.

American Indian tribes in the Upper Midwest were doing what they could to help members in need with heating supplies. The extreme cold was “a scary situation,” because much of the housing is of poor quality, said Chris Fairbanks, energy assistance program manager for the White Earth Band of Ojibwe in Minnesota.

The cold weather was even affecting beer deliveries, with a pair of western Wisconsin distributors saying they would delay or suspend shipments for fear that beer would freeze in their trucks.

But it wasn't stopping one of America's most formidable endurance tests, however - the three-day Arrowhead 135 was going on as scheduled in northeastern Minnesota. Competitors can cover the race route by bicycle, cross-country skis or just running.

The cold is attributed to a sudden warming far above the North Pole. A blast of warm air from misplaced Moroccan heat last month made the normally super chilly air temperatures above the North Pole rapidly increase. That split the polar vortex into pieces, which then started to wander, said Judah Cohen, a winter storm expert for Atmospheric Environmental Research.

One of those polar vortex pieces is responsible for the subzero temperatures across the Midwest this week.

Associated Press reporters Caryn Rousseau and Don Babwin in Chicago; Corey Williams, David Runk and Mike Householder in Detroit; David Eggert in Lansing, Michigan; and Jeff Baenen in Minneapolis contributed to this report. AP Science Writer Seth Borenstein also contributed. </s> BISMARCK, N.D. — A deadly arctic deep freeze enveloped the Midwest with record-breaking temperatures on Wednesday, triggering widespread closures of schools and businesses, and the canceling of more than 1,500 flights from Chicago’s airports. The cold even prompted the U.S. Postal Service to suspend mail delivery to a wide swath of the region.

Many normal activities shut down and residents huddled inside as the National Weather Service forecast plunging temperatures from one of the coldest air masses in years. The bitter cold is the result of a split in the polar vortex that allowed temperatures to plunge much further south than normal.

In Chicago, temperatures were still dropping after plunging early Wednesday to minus 19 degrees (negative 28 Celsius), breaking the day’s previous record low set in 1966. Snowplows were idled overnight in southwestern Minnesota, where temperatures dropped to negative 29 degrees (negative 34 Celsius). And the temperature in Fargo, North Dakota, was 31 degrees below zero (negative 35 Celsius).

In addition to the flight cancelations in Chicago at O’Hare International Airport and Midway International Airport, the extreme cold prompted Amtrak to cancel all trains into and out of Chicago.

Officials throughout the region were focused on protecting vulnerable people from the cold , including the homeless, seniors and those living in substandard housing. Some buses were turned into mobile warming shelters to help the homeless in Chicago.

Governors in Illinois, Wisconsin and Michigan declared emergencies as the worst of the cold threatened on Wednesday. In Chicago, major attractions closed because of the bitter cold, including the Lincoln Park Zoo, the Art Institute and the Field Museum.

“These (conditions) are actually a public health risk and you need to treat it appropriately,” Chicago Mayor Rahm Emanuel said Tuesday. “They are life-threatening conditions and temperatures.”

A wind chill of minus 25 (negative 32 degrees Celsius) can freeze skin within 15 minutes, according to the National Weather Service.

In Michigan, homeless shelters in Lansing were becoming “overloaded,” Mayor Andy Schor said. They also were filling up in Detroit.

“People don’t want to be out there right now,” said Brennan Ellis, 53, who is staying at the Detroit Rescue Mission Ministries.

Detroit’s outlook was for Wednesday overnight lows around minus 12 (negative 24 degrees Celsius), with wind chills dropping to minus 35 (negative 37 degrees Celsius).

At least four deaths were linked to the weather system Tuesday, including a man struck and killed by a snow plow in the Chicago area, a young couple whose SUV struck another on a snowy road in northern Indiana and a Milwaukee man found frozen to death in a garage.

A popular saying goes: “Neither snow nor rain nor heat …” will stop the mail from being delivered. But extreme cold will on Wednesday.

The U.S. Postal Service said it would suspend mail delivery on Wednesday in parts or all of several Midwest states including North Dakota, South Dakota, Nebraska, Kansas, Minnesota, Wisconsin, Iowa, Illinois, Indiana and Michigan.

Hawaii native Charles Henry, 54, was staying at a shelter in St. Paul, Minnesota, and said he was grateful to have a place to stay out of the cold.

“That wind chill out there is not even a joke,” he said. “I feel sorry for anybody that has to stay outside.”

Chicago was turning five buses into makeshift warming centers moving around the city, some with nurses aboard, to encourage the homeless to come in from the cold.

“We’re bringing the warming shelters to them, so they can stay near all of their stuff and still warm up,” said Cristina Villarreal, spokeswoman for the city’s Department of Family and Support Services.

Shelters, churches and city departments in Detroit worked together to help get vulnerable people out of the cold, offering the message to those who refused help that “you’re going to freeze or lose a limb,” said Terra DeFoe, a senior adviser to Detroit Mayor Mike Duggan.

Hundreds of public schools and several large universities from North Dakota to Pennsylvania canceled classes Tuesday or planned to do so Wednesday.

American Indian tribes in the Upper Midwest were doing what they could to help members in need with heating supplies. The extreme cold was “a scary situation,” because much of the housing is of poor quality, said Chris Fairbanks, energy assistance program manager for the White Earth Band of Ojibwe in Minnesota.

The cold weather was even affecting beer deliveries, with a pair of western Wisconsin distributors saying they would delay or suspend shipments for fear that beer would freeze in their trucks.

But it wasn’t stopping one of America’s most formidable endurance tests, however — the three-day Arrowhead 135 was going on as scheduled in northeastern Minnesota. Competitors can cover the race route by bicycle, cross-country skis or just running.

The cold is attributed to a sudden warming far above the North Pole. A blast of warm air from misplaced Moroccan heat last month made the normally super chilly air temperatures above the North Pole rapidly increase. That split the polar vortex into pieces, which then started to wander, said Judah Cohen, a winter storm expert for Atmospheric Environmental Research.

One of those polar vortex pieces is responsible for the subzero temperatures across the Midwest this week.

Associated Press reporters Caryn Rousseau and Don Babwin in Chicago; Corey Williams, David Runk and Mike Householder in Detroit; David Eggert in Lansing, Michigan; and Jeff Baenen in Minneapolis contributed to this report. AP Science Writer Seth Borenstein also contributed. </s> Tens of millions of Americans shivered for a second day as the mercury dipped to record lows in several states.

CHICAGO: Brutally cold temperatures gripped the US Midwest on Thursday (Jan 31), freezing water mains, causing power outages, canceling flights and straining natural gas supplies.

Tens of millions of Americans shivered for a second day as the mercury dipped to record lows in several states.

Ten deaths have been attributed to the sub-zero weather and a weekend snowstorm that deluged the same region. Many of the cold-related fatalities were in Michigan, where the governor said the death toll was still being confirmed.

Schools and businesses remained closed in several midwestern states, people were encouraged to stay home, and travelers were stranded by grounded flights and halted trains.

Natural gas supplies were under threat in Michigan and Minnesota. Authorities asked residents to reduce heat consumption wherever possible and decreased heating in government buildings.

Water mains froze in Detroit, Chicago and parts of Canada and power outages were reported in Iowa and Wisconsin.

Nearly 1,700 flights had been canceled in Chicago by Thursday afternoon. Airport crews worked in 15-minute increments on the tarmac to avoid frostbite.

Amtrak planned to begin restoring service to some trains after canceling all lines Wednesday in and out of Chicago.

The deadly, sub-zero temperatures were expected to lift on Friday, but the misery would not end quickly in the roughly dozen states most affected.

"We are not done yet. We've got another 24 hours where the weather will be at dangerous levels," Michigan Governor Gretchen Whitmer told a news conference.

The National Weather Service (NWS) said temperatures would slowly moderate, but the agency forecast wind chills Thursday would remain between -20 to -50 degrees Fahrenheit (-29 to -46 Celsius) over parts of the Upper Midwest.

The cold has frozen sections of Niagara Falls and sent blocks of ice floating down the river winding through Chicago's downtown.

MORE SNOW TO COME

The Arctic air mass that descended from its usual northern rotation on Wednesday caused the second coldest day ever recorded in the Windy City, where residents reported hearing "frost quakes."

Local television station WGN said booms heard by residents were likely frozen, water-saturated ground cracking under their feet.

The NWS said a low temperature of -21F (-29C) was recorded in Chicago on Thursday morning. The record low of -27F (-33C) was on Jan 20, 1985.

It said a historic low temperature for Illinois of -38F (-39C) had been reported in the town of Mt Carroll and was being reviewed before being declared a state record.

Record low temperatures were also reported in some towns in Iowa and Wisconsin.

Officials in multiple states warned that the extreme weather should be taken seriously, with the risk of hypothermia and frostbite setting in within minutes of exposure.

There were also concerns over another round of snow late Thursday, after a weekend snowstorm inundated the areas now frozen by Arctic cold.

"We've gone from snow to freezing temperatures, wind chill," Chicago Mayor Rahm Emanuel said at a news conference. "With more snow on the way, we're not out of the woods yet."

Hundreds of warming centers were opened for vulnerable residents such as seniors, and shelter capacities increased for the homeless.

Among the 10 reported dead this week was an 18-year-old University of Iowa student.

He was found unresponsive behind a campus building Wednesday morning, when wind chill temperatures in Iowa City were -51F (-46C), according to local TV station KCCI.

While officials warned residents to remain on guard as long as the sub-zero weather persisted, authorities in Michigan and Minnesota were also asking them to turn down their thermostats to conserve natural gas.

Supplies were strained due to high demand from home heaters and from a fire at a natural gas compressor station in Michigan, officials said.

"This is not over until noon tomorrow. And we are asking people to continue to keep the thermostat down," Michigan Governor Whitmer said.

General Motors and Fiat Chrysler suspended or curtailed operations at more than a dozen facilities in Michigan to conserve natural gas, the companies said.

City crews braved sub-zero weather to repair a number of frozen water main breaks that plagued Motor City neighbourhoods.

Chicago reported 22 broken water mains, 16 of which had already been repaired.

America's northern neighbour Canada was also contending with extreme cold, with frozen water pipes, snarled travel on a major waterway, and temperatures as low as -40F (-40C) on Wednesday. </s> A brutal cold wave moved eastward Thursday after bringing temperatures in the US Midwest lower than those in Antarctica, grounding flights, closing schools and businesses and raising fears of hypothermia.

The extreme weather has now been blamed for as many as eight deaths, US news outlets reported.

Mail deliveries were suspended and people were encouraged to stay home in nearly a dozen US states where the mercury plunged into the negative double digits, the worst freeze to grip the region in a generation.

The phenomenon stemming from a blast of Arctic air caused surreal scenes throughout the region, such as steam rising off the waters of Lake Michigan – the result of extremely cold air passing over warmer water below. Parts of Niagara Falls solidified into frozen stillness, and blocks of ice covered the river winding through downtown Chicago.

America’s third city was in the direct path of the harsh weather and experienced its second-coldest day ever. Chicago was on track to break new records overnight when temperatures were forecast to reach their lowest points in the early hours Thursday.

“They are life-threatening temperatures, and they should be treated accordingly,” he cautioned.

The most intense cold was expected overnight Wednesday into Thursday, said Ben Deubelbeiss, a meteorologist with the National Weather Service, The New York Times reported.

The Wednesday morning temperature in the Windy City was -22 degrees Fahrenheit (-30 Celsius), which felt like -50 degrees (-46 Celsius) with wind chill.

It was colder than Alaska’s state capital and even colder than parts of Antarctica.

“It feels like being close to dry ice,” Leon Gilbert, 31 said. “I can feel my skin tighten up.”

Unlike most Chicago residents, Gilbert was required to report to his job at a Starbucks on a downtown street largely devoid of its usual bustle of people and traffic.

Sandwich shop manager Daniel Gonzalez, 37, also reported to work – at 5:00 am.

“I have two shirts on… I have a hoodie, I have my big winter coat, I have a face mask and a skullcap and still cold,” Gonzalez said.

At Chicago’s O’Hare airport, a major regional hub for airlines, ground crews struggled with freezing equipment and were told to avoid spending more than 15 minutes at a time exposed to the cold, causing delays for flights that managed to take off.

More than 1,800 flights were cancelled at Chicago’s two major airports, while rail operator Amtrak scrapped train services from its hub in the city. </s> BISMARCK, N.D. — A deadly arctic deep freeze enveloped the Midwest with record-breaking temperatures on Wednesday, triggering widespread closures of schools and businesses, and the canceling of more than 1,500 flights from Chicago's airports. The cold even prompted the U.S. Postal Service to suspend mail delivery to a wide swath of the region.

Many normal activities shut down and residents huddled inside as the National Weather Service forecast plunging temperatures from one of the coldest air masses in years. The bitter cold is the result of a split in the polar vortex that allowed temperatures to drop much farther south than normal.

In Chicago, temperatures were still dropping after plunging early Wednesday to minus 19 degrees, breaking the day's previous record low set in 1966. Snowplows were idled overnight in southwestern Minnesota, where temperatures dropped to negative 29 degrees. And the temperature in Fargo, North Dakota, was 31 degrees below zero.

In addition to the flight cancelations in Chicago at O'Hare International Airport and Midway International Airport, the extreme cold prompted Amtrak to cancel all trains into and out of Chicago.

Officials throughout the region were focused on protecting vulnerable people from the cold , including the homeless, seniors and those living in substandard housing. Some buses were turned into mobile warming shelters to help the homeless in Chicago.

Governors in Illinois, Wisconsin and Michigan declared emergencies as the worst of the cold threatened on Wednesday. In Chicago, major attractions closed because of the bitter cold, including the Lincoln Park Zoo, the Art Institute and the Field Museum.

"These (conditions) are actually a public health risk and you need to treat it appropriately," Chicago Mayor Rahm Emanuel said Tuesday. "They are life-threatening conditions and temperatures."

A wind chill of minus 25 can freeze skin within 15 minutes, according to the National Weather Service.

In Michigan, homeless shelters in Lansing were becoming "overloaded," Mayor Andy Schor said. They also were filling up in Detroit.

"People don't want to be out there right now," said Brennan Ellis, 53, who is staying at the Detroit Rescue Mission Ministries.

Detroit's outlook was for Wednesday overnight lows around minus 12, with wind chills dropping to minus 35.

At least four deaths were linked to the weather system Tuesday, including a man struck and killed by a snow plow in the Chicago area, a young couple whose SUV struck another on a snowy road in northern Indiana and a Milwaukee man found frozen to death in a garage.

A popular saying goes: "Neither snow nor rain nor heat …" will stop the mail from being delivered. But extreme cold will on Wednesday.

The U.S. Postal Service said it would suspend mail delivery on Wednesday in parts or all of several Midwest states including North Dakota, South Dakota, Nebraska, Kansas, Minnesota, Wisconsin, Iowa, Illinois, Indiana and Michigan.

Hawaii native Charles Henry, 54, was staying at a shelter in St. Paul, Minnesota, and said he was grateful to have a place to stay out of the cold.

"That wind chill out there is not even a joke," he said. "I feel sorry for anybody that has to stay outside."

Chicago was turning five buses into makeshift warming centers moving around the city, some with nurses aboard, to encourage the homeless to come in from the cold.

"We're bringing the warming shelters to them, so they can stay near all of their stuff and still warm up," said Cristina Villarreal, spokeswoman for the city's Department of Family and Support Services.

Shelters, churches and city departments in Detroit worked together to help get vulnerable people out of the cold, offering the message to those who refused help that "you're going to freeze or lose a limb," said Terra DeFoe, a senior adviser to Detroit Mayor Mike Duggan.

Hundreds of public schools and several large universities from North Dakota to Pennsylvania canceled classes Tuesday or planned to do so Wednesday.

American Indian tribes in the Upper Midwest were doing what they could to help members in need with heating supplies. The extreme cold was "a scary situation," because much of the housing is of poor quality, said Chris Fairbanks, energy assistance program manager for the White Earth Band of Ojibwe in Minnesota.

The cold weather was even affecting beer deliveries, with a pair of western Wisconsin distributors saying they would delay or suspend shipments for fear that beer would freeze in their trucks.

But it wasn't stopping one of America's most formidable endurance tests, however — the three-day Arrowhead 135 was going on as scheduled in northeastern Minnesota. Competitors can cover the race route by bicycle, cross-country skis or just running.

The cold is attributed to a sudden warming far above the North Pole. A blast of warm air from misplaced Moroccan heat last month made the normally super chilly air temperatures above the North Pole rapidly increase. That split the polar vortex into pieces, which then started to wander, said Judah Cohen, a winter storm expert for Atmospheric Environmental Research.

One of those polar vortex pieces is responsible for the subzero temperatures across the Midwest this week. </s> CHICAGO: Bitter cold with temperatures lower than Antarctica gripped the American Midwest on Wednesday (Jan 30), grounding flights, closing schools and businesses and raising frostbite and hypothermia fears for homeless residents.



Mail deliveries were suspended and people encouraged to stay home in nearly a dozen US states where the mercury plunged into the negative double digits, the worst freeze to grip the region in a generation.

US media have attributed at least five deaths since the weekend to the freezing conditions and a major snowstorm that preceded the blast of Arctic air currently gripping the region.

In Chicago, blocks of ice floated on the downtown river of America's third-largest city and flames from gas burners heated regional commuter rail lines to keep them functioning.

The morning temperature in the Windy City was -22 degrees Fahrenheit (-30 Celsius), which felt like -50 degrees (-46 Celsius) with wind chill. It was colder than Alaska's state capital and even colder than parts of Antarctica.

"It feels like being close to dry ice, so I can feel my skin tighten up," Leon Gilbert, 31, told AFP.

Unlike most Chicago residents, Gilbert was required to report to his job at a Starbucks located on a downtown street largely devoid of its usual bustle of people and traffic.

More than 1,500 flights were canceled at Chicago's two major airports while rail operator Amtrak scrapped train services from its hub in the city.

The US Postal Service - known for its commitment to bringing the mail whatever the weather - suspended deliveries in parts of Indiana, Michigan, Illinois, Ohio, Iowa, the Dakotas and Nebraska.

The cause of the sub-zero chill was a swirl of arctic air that broke away from the polar vortex that usually encircles the North Pole.

"There's cold, and then there's COLD!" the National Weather Service (NWS) said. "Extreme and dangerous COLD!"

The agency predicted temperatures to remain 25 to 45 degrees below average through Thursday, with wind chill values as low as -25 to -55 degrees Fahrenheit (-32 to -48 Celsius).

"The dangerously cold wind chills could cause frostbite on exposed skin in as little as five minutes," NWS said.

Residents in Grand Forks, North Dakota awoke to a bone-chilling -35 degrees Fahrenheit, and it was -27 degrees in Minneapolis, Minnesota.

Authorities warned that the extreme temperatures were life-threatening, as Illinois, Michigan, and Wisconsin implemented emergency measures.

"The bitter cold temperatures pose a real risk to people across the state," Illinois Governor J.B. Pritzker said on Twitter after touring state emergency operations.

Michigan Governor Gretchen Whitmer said government offices would remain closed through Thursday and nonessential employees would stay home.

"The National Weather Service continues to predict dangerously cold sub-zero temperatures and the priority must continue to be on keeping people safe," Whitmer said in a statement.

Authorities and health experts warned that frostbite and hypothermia could set in in minutes in the extreme cold.

Warming centres were opened for vulnerable residents such as the elderly and shelter capacities increased for the homeless, including the approximately 16,000 people estimated to live on the streets of Chicago.

In Chicago and Minneapolis, buses were used as roving warming shelters for the homeless.

Chicago's regional electric train service was canceled due to wire problems caused by freezing temperatures, as gas burners heated rail switches to keep trains moving on a reduced schedule.

Flight cancelations piled up throughout the United States, with more than 2,500 by mid-afternoon, stranding travelers such as Brandon Robinson who was spending extra days in a downtown Chicago hotel.

"I'm here until they let me leave," Robinson told AFP. "All my flights have been cancelled."

Remnants of a weekend snowstorm continued to plague portions of the northeast US - with strong winds and blowing snow reducing visibility on the roads.

Heavy snow was forecast in the northern stretches of Maine and snow squalls were predicted for other parts of the east coast of the country. </s> Chicago has officially broken its coldest record for January 30 as a deadly arctic blast freezes large swaths of the Midwest.

Temperatures were still dropping after plunging early Wednesday to minus 19 degrees, breaking the day’s previous record low of 15 below, set in 1966. Snowplows were idled overnight in southwestern Minnesota, where temperatures dropped to negative 29 degrees. The temperature in Fargo, North Dakota, was 31 degrees below zero.

More than 1,500 flights were canceled at Chicago’s airports as plummeting double-digit subzero temperatures disrupt area air and rail transit.

The National Weather Service said the actual temperature was 23 below zero at Chicago’s O’Hare International Airport on Wednesday morning. Wind chills in northern Illinois were as low as 57 below in Rockford.

Officials have warned against venturing out into the dangerously cold weather, and the governor has issued a disaster proclamation.

The South Shore Line, which runs into northern Indiana, suspended its commuter rail trips Wednesday and said it expected limited service Thursday. Extreme weather conditions prompted Amtrak to cancel all trains into and out of Chicago on Wednesday and most services to and from Chicago on Thursday.

Some major Chicago attractions were not open Wednesday, and schools were closed.

The Associated Press contributed to this report.
Several hundred flights are cancelled in Chicago amidst an extreme cold wave bringing temperatures of −22 °F (−30 °C) to the region. Amtrak, Metra and South Shore Line have also cancelled services.