A 68-year-old woman died in Grand Canyon National Park after falling into dangerous rapids on the Colorado River while on a private boating trip.

Mary Kelley, from Steamboat Springs, Colorado, was nine days into her trip when she “entered the river at the top of Hance Rapid" around 11:18 a.m. on Thursday. The rapid is a “highly technical and powerful whitewater rapid" at the Colorado River's intersection with Red Canyon,” the National Park Service said in a statement on Friday.

Other members of her group were able to pull Kelley out of the water. CPR was performed but she remained responsive.

Grand Canyon National Park was alerted of the incident by a personal locator beacon from a non-commercial river trip. Park rangers eventually flew the park helicopter to the location to attempt to resurrect the woman, but the efforts were unsuccessful.

An investigation is currently ongoing and is being conducted by the National Park Service and the Coconino County Medical Examiner. No further information is available yet.