Millions face below-zero temperatures in US as winter storms bring Arctic air

Warnings of subfreezing conditions in Montana and the Dakotas as severe cold could push as far as northern Texas

Subfreezing temperatures across much of the US left millions of Americans facing potentially dangerous cold on Sunday as Arctic storms threatened near-blizzard conditions in the north-east and several inches of snow in portions of the south.

The National Weather Service warned that windy, subfreezing conditions in Montana and the Dakotas could push wind chills as low as -70F (-56C).