A woman walks her dog as the sun goes down along Lake Calhoun in Minneapolis, January 7, 2014.  The National Weather Service (NWS) said Tuesday's high is expected to be near zero. A deadly blast of arctic air shattered decades-old temperature records as it enveloped the eastern United States on Tuesday, snarling air, road and rail travel, driving energy prices higher and overwhelming shelters for homeless people. At least eight deaths have been reported across the country because of the polar air mass sweeping over North America during the past few days. Authorities have put about half of the United States under a wind chill warning or cold weather advisory. [Photo/Agencies]