A 57-year-old woman died on an eight-mile hike in Grand Canyon National Park on Sunday, when temperatures topped 100 degrees, park officials said.
Park rangers got a call about a hiker in distress at 6:30 p.m., and when the woman was found in a remote area of the park at 1 a.m. she was dead, the National Park Service said in a statement.
She was on a hike in the Tuweep area of Arizona, which is described as a remote region.
The heat was well over 100 degrees Sunday. A cause of death is under investigation, but the park warned of the dangers of extreme heat in a statement Monday.
Get top local stories in San Diego delivered to you every morning. Sign up for NBC San Diego's News Headlines newsletter.
National Parks
For more on this story, go to NBC News.