GRAND CANYON, Ariz. (KTVX) – A 68-year-old woman died during a boating trip at Grand Canyon National Park on Thursday, the U.S. National Park Service confirmed.

The fatal incident happened on the Colorado River, according to NPS.

Mary Kelley of Steamboat Springs, Colorado, was on her ninth day of a multi-day private boating trip. Authorities believe Kelly first entered the river at the top of Hance Rapid where Red Canyon intersects with the Colorado River at River Mile 77.

Officials say Kelley was pulled out of the river by members of her traveling group. She was unresponsive and CPR was administered before emergency crews arrived.

NPS says Hance Rapid is a “highly technical and powerful whitewater rapid that was formed by debris from flash floods that tore through Red Canyon.”

The cause of the woman’s death is still being investigated by the National Park Service and the Coconino County Medical Examiner.