Mike Kittrell / AP

Dauphin Street in Mobile, Ala. is impassable after a tornado touched down on Dec. 25, 2012. A Christmas Day twister outbreak left damage across the Deep South while holiday travelers in the nation's much colder midsection battled sometimes treacherous driving conditions that included freezing rain and blizzards.

NBC News’ Alex Johnson reports:

A major winter storm pummeled large parts of the U.S. on Tuesday, dropping heavy snow on the Southern Plains and spinning off damaging tornadoes in warmer areas southward. Treacherous holiday travel was expected to become even more of an ordeal by the time the storm arrives in the Northeast later this week.

The worst of the tornadoes hit Tuesday afternoon in Mobile, Ala., where about 21,500 customers remained without power Tuesday night, Alabama Power said.

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