A potentially historic, massive winter storm will slam more than half of the United States today, moving east as it brings heavy snow, widespread ice accumulation and dangerous cold.

A winter storm aimed at impacting large swaths of the country comes with a "very rare" ice warning for numerous states, atmospheric scientist Matthew Cappucci said on social media Friday.

At least 172 million people are now under winter alerts as a potentially historic storm impacts more than half the country starting on Friday.