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.

A rare, potentially historic winter storm is bringing heavy snow and icy conditions across the Gulf Coast while most of the country is facing dangerously cold temperatures from an arctic blast that arrived over the weekend.

Snow was falling in New Orleans, where as much as 8 inches were expected to accumulate by the end of the day, threatening to tie a record set in 1895.