Hundreds of thousands of people were left shivering in the dark after a massive ice and snow storm cut a swath across the United States, knocking down power lines, snarling traffic, grounding flights and forcing schools to close. Freezing rain on the southern end of the storm covered trees and bridges with brilliant ice crystals but made roads incredibly slick and dangerous from Texas to Pennsylvania. At least a dozen deaths were reported. The northern side of the snow dumped as much as a foot (30 centimeters) of snow in some areas of Ohio and the US east coast. And with a cold front moving in behind the storm it could be days before the ice melts and weeks before all the damage is repaired, officials warned. The storm formed Monday over the southern plain states and Texas and moved steadily east and north, Sullivan said. Some areas got ice on top of snow. The Oklahoma Highway Patrol responded to more than 1,000 weather related collisions on Monday and Tuesday, 130 of them involving injury. Two people were killed. More than a hundred accidents were reported from midnight to 9 am Wednesday in the city of Dallas alone and a two people died in Texas, the Dallas Morning News reported. Heavy ice brought down tree limbs and power lines, blew out transformers and caused a number of fires in Kentucky, where several cities were completely without power.