abc s elwyn lopez in charlotte tonight. reporter: tonight, a dangerous winter storm on the move, putting more than 100 million people on alert. the system already pummeling parts of the midwest with more than a foot of snow. sending cars sliding off roads. now taking aim at the southeast, threatening the region with damaging and even crippling ice and snow. this storm is a menace. reporter: at least four governors declaring states of emergency. here in the carolinas, crews are pouring in from out of state as they brace for widespread power outages that could last days. duke energy, the largest utility provider here, now estimating as many as 750,000 customers may be impacted. we hope it s not that bad, but when we look at history, we think it could be that bad, especially with the wind and the ice and the sleet. reporter: and in nearby tennessee, shoppers racing to stock up on food and other supplies, clearing out shelves. getting some groceries, some supplies before it get