LAKE GEORGE -- A bus 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 newspaper reported officials said the bus was taking people to visit a northern New York prison.

State police said the bus was operated by a private company, which they didn't name.

The woman who died wasn't immediately identified. State police said she was believed to have been from New York City.

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.