LAKE GEORGE (AP) — A bus transporting visitors to upstate prisons rolled onto its side and plowed into a rock ledge early Sunday on a highway in the Adirondacks in northeastern New York, killing a woman pinned underneath and hurting nine others, authorities said.

Police were investigating what caused the wreck around 3:15 a.m. on the Adirondack Northway in the town of Lake George, about 60 miles north of Albany.

The bus tipped onto its side, slid and veered into the rock a quarter-mile south of the highway’s Exit 21, Queensbury Fire Chief Joseph DuPrey told the Glens Falls Post-Star.

The impact tore down at least 50 yards of guiderails and left the highway strewn with food wrappers and other items, including fliers about services for prisoners’ families, according to the Post-Star.

The bus, operated by Angelic Tours and Shuttles Inc. of Fayetteville, N.C., was taking passengers to visit prisons in Ray Brook and Malone, state police said.

Phone message left at the company’s New York City and Fayetteville offices requesting comment were not immediately returned Sunday afternoon.

Police identified the woman as Curtrice E. Gravitt, 33, of New York City. She had head, neck and chest injuries, police said.

Three of the injured victims were in fair condition at Glens Falls Hospital, while the rest were treated and released, hospital officials said.

The highway was closed for hours between exits 20 and 21.

The cause of the crash remains under investigation, police said.