Yoshio Hosobuchi, 74, apparently died when his ankle became entangled in a harness around his waist, leaving him dangling upside down in a waterfall, Zion National Park spokeswoman Aly Baltrus said.
Hosobuchi and his 61-year-old wife were hiking in the Left Fork Canyon, also known as the Subway Slot Canyon, in the middle of the park on Tuesday, Baltrus said.
The 9-mile hike, one of the park's most popular ones, includes swimming across cold water ponds and rappelling to reach the canyon floor, she said.
"His wife said her husband wanted to cross it off his bucket list," Baltrus said.
The adventurous couple took a rappelling course the day before, Baltrus said.
Something happened that made Hosobuchi cut the harness around his waist and his foot became entangled in the harness, leaving him hanging upside down in the waterfall, Baltrus said.
"His hands were five feet from the canyon floor," she said. Hosobuchi's wife was unable to help and she started hiking out of the canyon, Baltrus said.
A group of people who were hiking ahead of Hosobuchi and his wife notified park rangers the couple probably would not make it out of the canyon by nightfall because they were hiking at a slow pace, according to Baltrus.
Hosobuchi and his wife were supposed to meet friends for dinner Tuesday evening and when they didn't show up, the friends notified park rangers at about 10 p.m., Baltrus said.
A search and rescue team encountered Hosobuchi's wife on the trail around 11:45 a.m. Wednesday and reached Hosobuchi that evening, Baltrus said.
She said the team hooked Hosobuchi up to their rappelling gear and cut him free of the harness, Baltrus said.
Hosobuchi was pronounced dead at the scene and was flown out Thursday morning by helicopter. The Utah State Medical Examiner's Office is conducting an autopsy on the body.
The Zion National Park website describes "The Subway" as one of the park's most popular canyoneering routes that requires several rope rappels.
It was the first death in the Subway Slot Canyon in recent history, but there are a number of rescues annually, according to park officials.
"The Subway is deceiving," Zion National Park Superintendent Jock Whitworth said in a news release.
Whitworth said the 9-mile hike requires rappelling and ascending skills, extensive route-finding experience and swims through several cold and deep pools.
"Unfortunately, its location inside the wilderness also means that rescues are not always possible or timely enough. Sound decision making and problem solving are critical," he said.