NEW ORLEANS — A rare frigid storm charged through Texas and the northern Gulf Coast on Tuesday, blanketing New Orleans and Houston with snow that closed highways, grounded nearly all flights and canceled school for more than a million students more accustomed to hurricane dismissals than snow days.

A major winter storm prompts blizzard warnings, dumping heavy snow and sleet in a region where even flurries are a rare sight.

Heavy snow, sleet and freezing rain are spreading east across parts of the Florida panhandle and eastern Carolinas, closing roads and schools and grounding flights.