Approximately 600,000 people go missing in the U.S. each year, with 8-11% disappearing without a trace, often due to unexplained circumstances.
Morgan Heimer, a 22-year-old river guide, vanished during an eight-day hike in the Grand Canyon on June 2, 2015; extensive searches yielded no trace of him.
Ruthanne Rupert, 49, disappeared in Yosemite National Park on August 14, 2000, after being left behind for medical treatment; her backpack was found eight years later, raising questions about her fate.
Paul Braxton, a park ranger, has been missing since January 13, 1980, after leaving the tourist center for a trek; despite extensive searches and a reward for information, he remains unaccounted for.
Stacey Ann Arris, 14, disappeared in Yosemite National Park in 1981 while on a guided tour; despite a large-scale search operation, only her camera lens cap was found.
The cases of missing individuals in national parks highlight ongoing concerns about safety and the mysterious nature of disappearances in remote areas.