A hiker from Window Rock passed away Sunday evening along the Thunder River Trail in the Grand Canyon National Park. National Park Service officials say 59-year-old Delphine Martinez was on a multi-day backpacking trip, hiking down the trial when she became disoriented and later unconscious at around 7:30 p.m. Trip members attempted to resuscitate her, but couldn’t and she was pronounced dead on the trail. High temperatures in the inner canyon were well over 100 degrees Sunday. Park rangers at the Grand Canyon National Park urge visitors to the canyon, especially inner canyon hikers and backpackers, to be prepared for excessively hot days in the coming weeks. In the summer, temperatures on exposed parts of the trail can reach over 120 degrees 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. An investigation into the death is ongoing.