Arctic temperatures, snow and flooding sweep across the U.S.

Tonight, 71 million people are under winter weather alerts as widespread snow wallops much of the country. The treacherous conditions causing this multi-vehicle crash in Illinois. And another huge pileup in Iowa.In Iowa City, wind chills at 20 to 30 below zero later tonight as major cities like Boston, Philadelphia, and New York are set to get their first measurable snow of the season overnight. proceeds straight east across the valley. You'll see a cluster of trees >> across the country.New video released ...