The hike was meant to be another challenge conquered by Dennis Smith, a 74-year-old retired surgeon from Washington known for pushing his limits. Instead, it turned tragic.

According to early reports, Dr. Smith collapsed near the end of a 24-mile rim-to-rim hike in Grand Canyon National Park on May 15, 2025. He was just half a mile from the North Kaibab Trailhead when he was found unresponsive around 4:45 p.m.

Efforts to save him failed. He was pronounced dead at the scene.

The Washington Surgeon Was an “Avid Hiker”

This wasn't his first difficult hike. Smith had a long track record of extreme endurance activities like ultra-trail runs, Iron Man races, and even climbing Mount Rainier. Friends and family say he was in great shape and took his health seriously.

The News / Officials haven't released the official cause of death of Dr. Smith. The Coconino County Medical Examiner is still investigating.

Temperatures during the hike reached nearly 100°F. While heat was initially suspected, park officials later said the weather was "relatively cool" when Smith collapsed.

Smith’s longtime friend and hiking partner, Dr. Tom Helpenstell, said the two trained hard for the hike. Smith had paid close attention to hydration, pace, and nutrition. Helpenstell called his death a “freak accident,” pointing to Smith’s deep knowledge of hiking and high-level fitness.

The Hike Is Fatally Challenging

The Grand Canyon’s rim-to-rim hike is no small feat. It stretches about 24 miles from the South Rim to the North Rim, plunging deep into the canyon and then climbing back up. The North Kaibab Trail, where Smith collapsed, is steep and demanding, especially in the final stretch.

The National Park Service also reminds hikers to carry plenty of water, know their limits, and plan for emergencies, since help can be hours away.

Smith’s death has left a mark on both the medical and hiking communities. Before retiring in 2021, he was a respected orthopedic surgeon, known not just for his skills but for mentoring younger doctors. After retirement, he didn’t slow down. He focused on health, hiking, and spending time with his grandchildren.

USA Today / During the warmer months, the park advises avoiding canyon hikes between 10 a.m. and 4 p.m., when heat becomes dangerous.

“He believed in staying active, always learning,” said his daughter, who described him as the kind of grandpa who would take the kids on hikes and teach them about fitness, food, and fun.

Still, the shock lingers. How could someone so fit and careful collapse so close to the end of a hike he had trained for?

Heat Exhaustion Is Common

The park is urging hikers to stay alert, even if they think they are prepared. Conditions in the canyon can change fast. Fitness doesn’t guarantee safety.

Even experienced hikers can experience heat exhaustion and dehydration, heart issues, altitude problems, and fatigue. The terrain pushes the body in ways that are not always obvious until it is too late.

The Grand Canyon, with all its beauty and scale, remains one of the most challenging hiking environments in the U.S. While thousands make the rim-to-rim hike each year, it is never routine. It demands planning, awareness, and respect.

Dr. Smith knew that better than most. And while his final hike ended in tragedy, his life left behind a trail of impact, from operating rooms to mountain peaks.