Updated

A bus transporting visitors to upstate prisons rolled onto its side and plowed into a rock ledge on a highway in the Adirondack mountains early Sunday, killing a woman pinned underneath and hurting nine other people, authorities said.

Police were investigating what caused the 3:15 a.m. wreck 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 newspaper. The impact tore down at least 50 yards of guide rails and left the highway strewn with food wrappers and fliers about services for prisoners' families, the newspaper said.

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

Three of the injured passengers remained hospitalized Monday. A spokesman for Glens Falls Hospital said two were in fair condition following surgery and the third was in serious condition.

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

The highway, part of Interstate 87 running from north of Albany to the Canadian-U.S. border, was closed for hours around where the crash happened.