A rare winter storm charging through Texas and the northern Gulf Coast on Tuesday has closed highways and airports and prompted the first blizzard warning for southeast Texas and southwest Louisiana.

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.

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.