GRAND CANYON, Ariz. (ABC4) – A backpacker was reported dead on Thunder River Trail in Grand Canyon National Park on Sunday, Sept. 4. 

Delphine Martinez, 59, of Window Rock, Ariz. was reportedly on a multi-day backpacking trip. While hiking down the Thunder River Trail on Sunday, she became disoriented and later unconscious. Other members of the trip attempted to resuscitate Martinez but were unable to. 

On Sunday, high temperatures in the inner canyon were well over 100 F, with the high temperature at Phantom Ranch at approximately 115 F. 

Grand Canyon National Park Rangers urge visitors to be prepared for excessively hot days in the coming weeks, especially for inner canyon hikers and backpackers. During the summer months, temperatures on exposed parts of the trail can reach over 120 F in the shade. Park rangers strongly advise not hiking in the inner canyon during the heat of the day between the hours of 10 a.m. and 4 p.m. 

“Hiking in extreme heat can lead to serious health risks including heat exhaustion, heat stroke, hyponatremia, and death,” Grand Canyon National Park officials said in a statement.

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

No additional information is available at this time.