A Canadian woman died while hiking in Grand Canyon National Park in Arizona, the National Park Service (NPS) says.

Melanie Goodine, 41, was hiking Thursday out of the canyon along the Bright Angel Trail, near Three-Mile Resthouse, when officials received a report she was in distress, the NPS said in a news release.

“Soon thereafter the hiker became unresponsive and bystanders initiated CPR,” the release read. “National Park Service (NPS) search and rescue personnel responded and assisted with resuscitation efforts. All attempts to resuscitate the individual were unsuccessful.”

Goodine was making her way out of the canyon after hiking to the Colorado River earlier in the day.

Shade temperatures in the area Goodine was hiking reached a high of about 95 to 104 on Thursday, Joelle Baird, a spokesperson with Grand Canyon National Park, told CNN. Depending on the trail taken, the path Goodine hiked can be up to 20 miles round trip.

“The NPS does not recommend hiking from the rim to the river and back in one day,” their statement read.

An investigation into the incident is currently underway by the NPS in coordination with the Coconino County Medical Examiner.

“Before heading down trail, hikers are strongly encouraged to read the Hiking Tips page and check the Backcountry Updates and Closures page for current information on inner canyon conditions,” the statement said.

“All visitors to Grand Canyon should ensure they are drinking plenty of fluids, resting in shade during the heat of the day, watching for signs of distress in traveling companions, and dressing appropriately for the weather, which includes light-colored and loose-fitting clothing.”