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.

At least three deaths were attributed to the cold as dangerous below-freezing temperatures with even colder wind chills settled in.

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.