A major storm spread heavy snow, sleet and freezing rain across the southern United States on Wednesday, breaking snow records and treating the region to unaccustomed perils and wintertime joy.

Most of the United States is being assailed with extreme winter weather this week as Arctic air blasts south from Canada, snow tracks up the Northeast coast and a potentially crippling winter storm takes aim at the South.

Travelers heading to some of the nation's busiest airports in the next two days should expect delays and canceled flights.