STORY: The first major U.S. winter storm system of the year posed a tornado and flood threat to a large swath of the South, and dumped a frosty mix of snow, freezing rain and sleet from the Northern Plains to the Upper Great Lakes region on Tuesday.

The wintry blast, expected to spread into New England by Wednesday (January 4), was part of a larger weather front bringing heavy showers, severe thunderstorms, hail and tornadoes to the lower Mississippi Valley, Gulf Coast, Tennessee Valley and southern Appalachians.

Tornado watches and severe thunderstorm warnings were in effect across much of Louisiana, Mississippi, Alabama and Georgia, along with flood watches posted along the southern fringe of that zone.