A 67-year-old man whose body was found in Yellowstone National Park died of exposure — specifically hypothermia, park officials announced Wednesday.
Mark O’Neill, of Chimacum, Wash., was found dead Sept. 20 on the east shore of Shoshone Lake, Yellowstone’s second-largest lake. His brother Kim Crumbo, 74, is still missing in the park. The dayslong search transitioned from a rescue to a recovery effort on Friday.
An autopsy revealed how O’Neill, 67, died, according to a National Park Service news release. Relatives had reported the two brothers overdue from a backcountry trip on Sept. 19, when they didn’t return from their expected four-night excursion.
Crews continue to look for Crumbo, a well-known conservationist from Ogden. Teams are searching near Shoshone Lake on foot and by boat, and with the help of dog teams, a helicopter and sonar. The park service says the recovery effort will continue for the next several days “as conditions warrant.”
Shoshone Lake is prone to high winds, according to the National Park Service’s backcountry situation report, and its average water temperature is a cold 48 degrees.
“Survival time is estimated to be only 20 to 30 minutes in water of this temperature,” the park service said in a prior news release.
Officials are still investigating what happened to the two men. Anyone with information that could help investigators, or anyone who was in the Shoshone Lake area between Sept. 12-19, may call 307-344-2428 or email firstname.lastname@example.org.
Both Crumbo and O’Neill were retired from the National Park Service. Crumbo’s two decades of service included working as the river ranger and wilderness coordinator in Grand Canyon National Park, as well as a park ranger. The former Navy SEAL also had advocated for the protection of wild places with several conservation groups in Utah and across the West.
The park service had previously reported that O’Neill and Crumbo were half-brothers, but they are brothers, according to Wednesday’s news release.