Brutal cold grips U.S. Midwest

Extreme cold and record-low temperatures are sweeping through parts of the United States, especially the Midwest.
For more on this and other news around the world we turn to our Ro Aram…
Aram… we are having a mild winter here in Korea,... but it's literally the polar opposite in the U.S....

That's right, Mark… Weather authorities are warning this cold wave could be life-threatening.
The brutal chill was caused by the polar vortex, a mass of freezing air that normally spins around the North Pole, but has made its way south into the United States.
The Midwest will be hardest hit, experiencing temperatures not seen in a quarter century.
The Chicago area and northern Illinois are forecast to see the mercury dip to almost minus 50 degrees Celsius - temperatures usually found in the Arctic Circle.
The mercury in other areas will hover around minus 20.
Bone-freezing wind chills will be accompanied by heavy snow, with as much as 60 centimeters expected in Wisconsin.
Schools in several cities have been closed and hundreds of flights have also been cancelled.
People are being advised to stay indoors as those outside in the intense cold could experience frostbite within 10 minutes.
Dozens of warming centers have also been set up.
Temperatures were expected to be at their coldest on Wednesday.