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.

A rare and potentially historic winter storm is bringing heavy snow to Texas and the Gulf Coast while nearly 220 million people across 40 states are facing dangerously cold temperatures from an arctic blast that arrived over the weekend.