As millions of Americans hunker down for a massive winter storm sweeping the country, new maps are offering updated forecasts of snow and ice accumulations.

A fierce winter storm swept into the West on Friday with freezing rain and snow, while a blast of polar air helped send temperatures plunging as low as minus 58 degrees in the Northern Plains.

A powerful winter storm is peaking as it moves east, battering the Midwest, Great Lakes and Northeast with blizzard conditions, damaging ice, widespread power outages and major travel disruptions.