A rare winter storm churned across the U.S. Gulf Coast on Tuesday, bringing heavy snow, ice and wind gusts to a region where flurries are unusual, while much of the United States remained in a dangerous deep freeze.

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 used to hurricane dismissals than snow days.