Millions of people across the northern Gulf Coast braced Tuesday for a rare winter storm that’s expected to scatter heavy snow, sleet and freezing rain around the Deep South as a blast of Arctic air plunges much of the eastern U.S. into a deep freeze.

Historic snowfall is burying parts of the Gulf Coast amid dangerous cold as a once-in-a-generation winter storm wreaks havoc on travel in a region wholly unaccustomed to winter weather. Footage from across the Gulf Coast showed snow in implausible places,