A backpacker from Arizona died Sunday on a multi-day trip through Grand Canyon National Park, authorities said Tuesday. Delphine Martinez, 59, was found dead by park officials after a report came in from the Thunder River Trail around 7:30 p.m. Amid triple-digit temperatures, Martinez reportedly became disoriented and eventually lost consciousness. Other hikers with Martinez attempted life-saving measures, but were unsuccessful. Temperatures in the inner canyon on Sunday soared well above 100 degrees, according to KTVX. “Hiking in extreme heat can lead to serious health risks including heat exhaustion, heat stroke, hyponatremia, and death,” park officials said in a statement, reiterating a warning against hiking the inner canyon between 10 a.m. and 4 p.m. during summer. An investigation into Martinez’s death remained ongoing Tuesday.