Widespread damage from a deadly ice storm left more than half a million customers still in the dark Friday night, and utility officials said the electricity might not be fully restored in parts of the Carolinas until Tuesday.

The storm blew through Georgia, the Carolinas and Virginia on Thursday and was blamed for hundreds of traffic accidents and at least four deaths. Ice built up on tree limbs, causing them to snap and pull down power lines.

Duke Power, the leading electricity provider in the hard-hit areas, said the storm inflicted "extreme structural damage" that kept 536,000 customers in the Carolinas without power Friday evening, down from 683,000 at the height of the storm.

The company urged customers facing extended periods without heat to find another place to stay.

About 7,500 utility technicians were on the job, Duke said.

Power was restored more quickly in Georgia, where the remaining 30,000 homes and businesses still without electricity Friday afternoon were expected to have power by morning.

Schools remained closed Friday in Virginia and Maryland, and the ice left commuters with more tough driving conditions south to Georgia.

At least four deaths were reported from the storm as the storm moved up the East Coast. Two men died in Maryland and another died in Georgia after the freeze made driving treacherous. In suburban Charlotte, a 58-year-old man died when a tree buckled from heavy ice and crushed him in his home.

North Carolina's heaviest icing — one-half to three-quarters of an inch — came in the southwestern area of Saluda and Flat Rock, said Doug Outlaw of the National Weather Service's bureau at the Greenville-Spartanburg Airport in South Carolina.

Virginia Tech delayed graduation ceremonies for more than 2,500 students Friday.