Hugh Pickens DOT Com writes "Reuters reports that the Midwestern United States is shivering through the region's lowest temperatures in twenty years as forecasters warn that life-threatening cold is heading eastward as a polar vortex of freezing Arctic weather sweeps across the United States. 'The coldest temperatures in almost two decades will spread into the northern and central U.S. today behind an arctic cold front,' says the National Weather Service. 'Combined with gusty winds, these temperatures will result in life-threatening wind chill values as low as 60 degrees below zero (Fahrenheit/minus 51 degrees Celsius).' The coldest temperature reported in the lower 48 states on Sunday was minus 40 F (-40 C) in the towns of Babbitt and Embarrass, Minnesota. Meteorologists warn that the wind-chill factor could make it feel twice as cold, causing frostbite to exposed parts of the body within minutes. Eleven people have already died in weather-related incidents in the past week, including a 71-year-old woman with Alzheimer's who wandered from her home in upstate New York and was found frozen to death only 100m away. Polar vortexes occur seasonally at the North Pole, and their formation resembles that of hurricanes in more tropical regions: fast-moving winds build up around a calm center. Unlike a hurricane, these are frigid polar winds, circling the Arctic at more than 100 miles per hour. The spinning winds typically trap this cold air in the Arctic. But the problem comes when the polar vortex weakens or splits apart, essentially flinging these cold wind patterns out of the Arctic and into our backyards. 'All the ingredients are there for a near-record or historic cold outbreak,' says meteorologist Ryan Maue. 'If you're under 40, you've not seen this stuff before.'"