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 massive winter storm is set to batter much of the US with ice, heavy snow and extreme cold, threatening power outages, travel chaos and dangerous wind chills affecting nearly 140 million people.

Millions are under weather alerts from the Southwest to the Northeast, with officials warning of major disruptions for days.

Note: The graphic shows the chance of receiving 4 inches or more of snow or ice. Click your area to see the forecasted probability over the next three days USA TODAY’s snowfall map shows accumulation over the past 24,

Arizona is expecting unsettled weather with rain and high-country snow through the weekend.

Nick Petro, a meteorologist for NWS Raleigh, said in a separate briefing Thursday that forecasters are "fairly confident that many places across central North Carolina will see a quarter inch of ice a...