NEW ORLEANS (AP) — 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 snowstorm warning was in effect for 31 million people - from southern Texas east through Georgia and north to the Carolinas and into Virginia - until Wednesday morning, the National Weather Service said.