It's something very weird and nuanced going on right now,’ says one expert about the potential reasons for the snow blanketing much of the southern U.S.

A major winter storm slammed the US Gulf Coast Tuesday, blanketing parts of a region largely unaccustomed to extreme winter weather with record-breaking snowfall.

Weather forecasters and public agencies issued health and power loss warnings Tuesday as a “rare winter storm" gripped parts of the southern and eastern United States."A bitterly cold airmass will remain in place for much of the South and eastern U.