Nearly a million American homes are without power as a massive winter storm sweeps the country.

According to poweroutage.com, the most impacted areas are in the south central U.S. to the southeast.

"The worst outages are now in Tennessee and Mississippi as ice continues to build up, bringing down trees and power lines," the outage tracking site reports.

Nearly 290,000 were without power in Tennessee and 140,500 in Mississippi as of mid-morning Sunday.

In Texas, nearly 134,000 were without power; in Louisiana, 121,000; in Kentucky, 56,000; in Georgia, 125,000.

"A significant winter storm is underway, bringing widespread heavy snow, sleet, and freezing rain from the Southern Rockies to New England through Monday," the National Weather Service reports. "Extremely cold air will follow, prolonging dangerous travel and infrastructure impacts into next week. Severe thunderstorms may produce damaging gusts and tornadoes across the eastern Gulf Coast states Sunday morning and afternoon."

New England states are expected to get up to 18 inches of snow into Monday.

"Furthermore, heavy rain will develop over the Lower Mississippi Valley on Sunday and parts of the Tennessee Valley on Monday," NWS says. "In the wake of the storm, communities from the Southern Plains to the Northeast will contend with bitterly cold temperatures and dangerously cold wind chills. This will cause prolonged hazardous travel and infrastructure impacts."