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US freeze forces polar bear indoors

A blast of Arctic air that has gripped the vast middle of the United States has forced a polar bear at a Chicago zoo indoors, according to local media reports.

Anana, a polar bear at Lincoln Park Zoo has not yet grown a layer of blubber that bears need to insulate themselves against arctic winter temperatures and will be staying warm inside a “climate-controlled” area.

Chicago saw a record low of -27 C on Monday. Credit: Reuters/Jim Young

"In the wild, they would seasonally eat seals and fatten themselves up with that blubber," Lincoln Park Zoo spokeswoman Sharon Dewar told CNN.

But zookeepers "don't feed them seals or fatten them up," she said.

The U.S. cold snap outdid freezing weather in Almaty, Kazakhstan, where it was -22C and Mongolia at -23C.

More than half the flights at Chicago's O'Hare International Airport were canceled as fuel supplies froze, leaving crews unable to fill aircraft tanks. The afternoon temperature in Chicago yesterday dipped to minus -24C.

More snow on the way for Great Lakes cities

There is a high chance of more snow in the Great Lakes region of the US where temperatures remain at a record low, according to the National Weather Service.

Cities in the region have been blanketed in snow as a so-called polar vortex - an area of cold air that normally hovers over the polar region - was pushed south over Canada and the US.

A couple walks their dog past a snowman near the State Capitol building in Indianapolis, Indiana Credit: REUTERS/Nate Chute
Pedestrians walk past mounds of snow during bitter cold temperatures in downtown Detroit, Michigan Credit: REUTERS/Rebecca Cook
A woman walks through a gust of blowing snow in frigid cold temperatures though downtown Chicago, Illinois Credit: REUTERS/Jim Young

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Americans warned of 'dangerously low temperatures'

The National Weather Service has warned that the "dangerously low temperatures" will persist in many parts of the US on Tuesday.

Large parts of the eastern US have been issued freeze warnings (coloured blue) Credit: National Weather Service

The weather system is beginning to creep eastwards but temperatures will remain on average around 20 degrees (Fahrenheit) below where they should be for the time of year.

NBC News reports that Hawaii is the only state in the country that is not affected by freezing temperatures.

Cold weather disrupts train services in US

US train operator Amtrak is reporting disruptions to its north-east services due to the extremely low temperatures.

Services have been suspended between Philadelphia and Baltimore, although it was not clear if this was weather-related.

Thousands of flights cancelled across US

Around 3,364 flights were cancelled and 3,155 delayed due to plummeting temperatures in the US, FlightAware.com reported.

US airline carrier JetBlue Airways grounded flights for 17 hours. Credit: Reuters

Major US airline JetBlue Airways today grounded flights for 17 hours at four of the busiest airports in the country.

More than half of the flights in or out of Chicago's O'Hare International Airport were cancelled after temperatures in the Windy City plunged to -15.

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What is a polar vortex?

The polar vortex, or polar pig, as it has been dubbed by some media commentators, is:

  • A large dense area of cold air formed in a polar winter
  • Normally found rotating hurricane-like around the North or South Pole
  • A low pressure area with winds that can exceed 100mph
  • Around -80 degrees Celsius
  • Strong enough to sustain its own low pressure, sealing in cold air like a fridge
  • Tens of thousands of feet above the atmosphere
  • Able to cause extremely cold conditions if its vortex is disturbed or deteriorates
  • Rarely found in inhabited areas, but has moved south like an Arctic cyclone
  • Possibly further south than normal due to a build up of warmer areas in Greenland or Alaska.

'Chiberia' residents battle frigid cold temperatures

Chicago residents braved the outdoors today as a blast of Arctic air grips the mid-section of the US.

A man is silhouetted against the arctic sea smoke rising off Lake Michigan in Chicago. Credit: Reuters

America is expecting its coldest temperatures in two decades, with meteorologists warning that temperatures were dangerously cold and life-threatening in some places.

A woman covers her head with a jacket as she walks though downtown Chicago. Credit: Reuters

Temperatures of -18 were recorded in Chicago - nicknamed "Chiberia" - St. Louis and Indianapolis, with the chill set to bear down on eastern and southern states as the day wears on.

A woman covers up in multiple layers for a walk in downtown Chicago. Credit: Reuters
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