Atlanta (Reuters) - At least three people had died and thousands of homes were left without power in the Carolinas and Virginia early on Tuesday after a storm dumped up to two feet of snow in parts of the southeastern United States.

One person died from a heart condition while en route to a shelter and a terminally ill woman died when her oxygen device stopped working, North Carolina Governor Roy Cooper’s office said in a statement. A motorist also died in southwestern North Carolina on Sunday when a tree fell on the vehicle, police said.

More than 70,000 customers remained without electricity in the region as of 5 a.m. local time Tuesday, down from a high of 220,000 on Monday, Poweroutage.us reported. Weather warnings remained in effect.

“The danger is black ice, ice that’s difficult to see on roads, caused by the re-freezing of snow melt,” said David Roth, a forecaster with the National Weather Service’ Weather Prediction Center in College Park Maryland.

“It’ll be a risk for the next few mornings, probably through Thursday morning, before we see persistent temperatures above freezing in the area,” he said.

Because of icy roads, scores of schools canceled or delayed classes Tuesday across northern Georgia, North Carolina and Virginia. Many government offices also delayed opening Tuesday for non-essential personnel.

Late Sunday and early Monday, the storm dropped its heaviest snow in the appropriately named Whitetop, Virginia, tucked in the Appalachian Mountains along the western end of the Virginia-North Carolina border, the U.S. National Weather Service said. Whitetop got two feet of snow. Greensboro, North Carolina, had 16 inches (41 cm) and Durham, North Carolina, 14 inches (36 cm).

Temperatures were expected to rise above freezing by late morning but will drop back below freezing overnight through Thursday, Roth said. By Friday, temperatures should reach into the 50s Fahrenheit in North Carolina east of the mountains when there is a chance of rain.

No widespread flight delays were reported early Tuesday by the major airports in the southeast, according to the flight-tracking website FlightAware.

The storm, at its height, prompted the cancellation of one in four flights into and out of Charlotte/Douglas International Airport, the sixth-busiest in the country, and other airports across the region, FlightAware said.