The second winter snowstorm in a week blanketed the East Coast with up to a foot of snow, tangling rush-hour traffic, delaying flights and closing schools. Across the nation's midsection, bitter cold air from Canada hit record lows in at least six cities. In Sheridan, Wyo., it was 19 below. The fast-moving storm spread snow from Tennessee and Illinois to the Atlantic Coast and north into New England as it rolled east. A mixture of snow and freezing rain pelted the Southeast. At least four deaths have been blamed on the storm.