Dangerous below-freezing temperatures with even colder wind chills were also expected to last over much of the week in the region. Authorities say three people have died in the cold weather.

Around 40 million people in the U.S. are under a winter storm warning from an unusual blast of severe winter weather.

Online tracker FlightAware says nearly 2,000 flights within the U.S. or entering or leaving the country were canceled Tuesday with about 10,000 more flights delayed.

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.

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 winter storm dumped snow across the Deep South Tuesday, leaving areas that rarely see this kind of weather with dangerous travel conditions, widespread airport closures and snow days. Here’s what it looked like from Texas across Louisiana,