ANDERSON, S.C.—South Carolina authorities say a 33-year-old Georgia woman has drowned in Lake Hartwell.

Crystal Sabrina Lester of Athens was walking in shallow water Wednesday afternoon when she went underwater and did not resurface, Deputy Anderson County Coroner Don McCown said.

Lester stepped off a ledge into water that was about 13 feet deep, McCown said. It took rescuers about an hour to find her body.

McCown said low lake levels have made it difficult for even experienced swimmers and divers to keep track of where the water becomes deep. This is the sixth consecutive year that someone has drowned on Lake Hartwell during the July 4th holiday, he said.