A major snowstorm blew across Colorado toward the Plains on Wednesday, canceling hundreds of airline flights for holiday travelers and shutting down major highways in parts of four states. The National Weather Service posted blizzard warnings for most of eastern Colorado and adjoining sections of Nebraska and Kansas. A day earlier, the storm had pummeled New Mexico with up to a foot of snow. Two feet of snow was possible in the foothills just west of Denver, with 2 to 3 feet a possibility farther north. Up to 20 inches could accumulate on the Plains of eastern Colorado and wind...