Millions of people from the Midwest to the Northeast are on alert as a developing winter storm is expected to bring a potentially crippling ice threat that could knock out power and lead to treacherous travel conditions across the region.

A developing winter storm could bring a potentially crippling ice threat from the Midwest to the Northeast, and the West Coast remains on alert for flooding as a series of atmospheric river storms swamps the region.

A potentially dangerous ice storm is set to slam millions of people from the Midwest to the Northeast starting Wednesday, and that could lead to power outages and treacherous travel from Chicago to Boston.