How Ultramarathon Runners Took on World's Most Difficult Trail

Timothy Olson moves along a path at just over 16,000 feet on day 11 of the expedition.

Two years ago, mountaineer Ben Clark took on what’s widely considered the most difficult trail in the world. He had his sights set on completing the Snowman Trek, a grueling route through the Himalaya in Bhutan.

The crescent-shaped trail starts on the northern border of Bhutan in Paro and snakes about 200 miles to Bumthang, covering roughly 48,000 feet uphill through rugged terrain. It traverses the peaks and valleys of 11 mountain passes, spanning a landscape often pummeled by fierce snow and rain storms. (Related: “World’s Happiest Country Also Has No Carbon Emissions”)

It normally takes a month to complete the trail, which can only be done when the weather is calm. Clark wanted to break the record and finish it in half that time.

Clark gathered together a team of ultramarathon-running friends, including Timothy Olson and Anna Frost, to join him on the adventure. He also enlisted a local guide named Wang Chuk, five cooks, and two horse attendants, along with 21 horses.

Mountain peak in Nepal Himalaya

None of the travelers had completed the route in its entirety before, and some of the locals were skeptical the team could complete it in the two-week timeframe. The Snowman Trek has a 50 percent success rate, and poor conditions force most intrepid visitors to turn back.

After powering through unforgiving storms, hypothermia, and mountain sickness, the team completed the trek in 15 days and nine hours.

Evening view of Ama Dablam

These days, 38-year-old Clark lives in Brooklyn. He’s retired from adventures like the Snowman Trek, but he continues to tell stories through cinematography. He runs about 50 miles each week now, instead of the 70-mile weeks he was pulling while training for the trek.

“I cannot spend all my time in the mountains and that’s just fine,” Clark says. “But if I don’t continue to share what it is I love about the mountains, then I feel like my life is just not fulfilling.”

National Geographic caught up with a jet-lagged Clark—calling from New York, a quick stop on his way from China to Australia.

Why did you decide to take on the Snowman Trek?

From 2002 until 2012, the most important thing in my life was how am I going to get to the Himalaya and explore high altitude mountains. I love climbing rock and ice and skiing and pioneering routes in those disciplines of high altitude. And when my son was born—who is now six—I decided that I didn’t want to take those kinds of risks anymore. When I stopped climbing mountains in 2012 from the more risk-exposed side, I decided to take up trail running.

I loved being in the mountains. Having been an alpinist and someone who is really a minimal, fast, light traveler through the mountains, trail running just made the most sense, because you really just needed a pair of shoes, a light backpack, and the better part of the day to do things that would have taken a lot longer if I was hiking. And so, as I developed that skillset, I continued to look back to the Himalaya and thought, “Gosh, there’s got to be something here that really would allow me to get deep back into these mountains that have shaped so much of my perspective and have been my focus.”

Knowing that you couldn’t travel above 6,000 meters in Bhutan—you’re never going to be allowed to climb those mountains—and knowing that this trek was called the world’s hardest trek by a number of folks and websites, I thought, “I really need to check this out.” And there’s no fear of suddenly feeling like while I’m there I [will] go run off and climb a peak.

This became the goal that drove me back [to the Himalaya] and allowed me to accomplish something greater than just another high altitude summit.

How did you prepare for the Snowman Trek?

Trail runner sportsman in winter snowy outdoor

I think every adventure is the culmination of all experiences that I’ve had in my life. Typically, I’m looking for something that’s going to be a new addition or building on the base and foundation of expected skills that I use to explore anyway. What I had done specifically to train for the Snowman Trek was just take up longer ultra-marathon distances.

When you get to Bhutan, you have those regulations that keep you from being able to go too fast. So I was able to train from Brooklyn running around Prospect Park, which is the second most popular run in the United States. I trained all summer and continue to run around Prospect Park—my little three-and-a-half-mile loop—as many times a day that I needed to to keep my endurance. The Snowman Trek is something you can actually be fit enough to do without having a base that requires you to pull 20-mile day after 20-mile day.

How did you pick your team for the Snowman Trek?

Hiker walks on train in Himalayas

 As exciting and exotic and cool as an opportunity it sounds like, from 2012 on until we finally got to do it in 2016, I was always soliciting. It was a matter of constantly talking about it and being excited about it like I would any other project in the Himalaya.

View of Everest from Gokyo ri . Nepal

 One night, Timothy Olsen and I and another friend went and did this huge nighttime climb over Mount Princeton. We started at 10:00 p.m. and we got over to the other side of the mountain around dawn. It was a cold night, it was wet, it had been a nasty day. [But] we kept kind of feeding off each other and wanting to keep going because it’s so adventurous and I thought, “Wow, anybody who likes this surely might also be open to some of the hardships we might encounter on the trail in Bhutan.” So Timmy was like, “What else do you got going on?” and I was like, “Hey, I really want to do this thing.”

Himalayan Mountains View from Mt. Shivapur

 He was one of the few people who got back to me and said, the next day, “Send me the information on that. I want to go do that.” And naturally, because he is a very mindful individual and those techniques have translated into success for him in the ultra-marathon world, the Eastern culture, I think, reflected his values and an experience he wanted to have. And I certainly felt that anyone who wanted to do that nighttime run to Mount Princeton had more than enough spirit to enjoy an adventure like this.

Annapurna Base Camp Trek

Luckily, another friend joined us—Anna Frost from New Zealand, who is a very wise and experienced ultramarathon runner. She had been going to Bhutan and leading some guided tours, and a friend connected us and we spoke about it. She said, “Well, I’ve already been over there, and if you guys are going, I want to do this.” So we discussed it and we decided that we would love to have her, because she is so knowledgeable and had experience in the country. And then from there, I worked with some former Nepali liaisons to help find the right guide service and to put together the right team in-country to actually help us execute it.

What were some of the unanticipated challenges you faced on this trek?

Kangchenjunga mountain view

When you start an adventure, you’re driven by the unknown. There’s a certain level of uncertainty, there’s a certain level of challenge, and there’s a mystique about the magic and majesty you’re going to encounter on the trail and in the mountains.

The most important unanticipated challenge for us was balancing those expectations [from] all the excitement. You think of all these amazing scenarios, but you still come into it with an expectation of how long we [were] really going to take to do this.

Climber in Mount Everest,Himalayan

Part of that, of course, became how do we as ambassadors of trail-running onboard the locals to believe this is actually possible, because no one believed it was possible until pretty much the last day we accomplished our goal in the time that we had set out to do it.

What was your favorite part about this trek?

View of Himalayas range in the morning from the flight.

 I went over there wondering what was possible, and as an explorer, it’s so gratifying to come away from it and not be spitting off stats about this trail. It was a tactile experience. It was amazing to be alive there. The locals were just so incredibly willing to change the way they did things to help us accomplish this goal. And then to share this goal—all of us set this record together and none of us had met before we started.

Hiker walks on train in Himalayas

To take that type of risk, to go out, to believe in these people, to do something everybody believes is impossible—that sort of revelation is incredible, because it’s so much deeper and so much more in tune with the human spirit.

I felt so fortunate to walk away with lasting relationships and to know that they have changed—because we all did this—the way things can be done in Bhutan. Now they know this is possible, and the idea of running through trails will help them—I hope—bring a whole new audience of people to that country.

How was this trek different from other adventures you’ve been on?

The other adventures I’ve been on really have been about pioneering things in the mountains that had just never been done. Something [being] unlikely to be completed really drove me, and those are [activities that had] a certain remoteness and a sense of solitude. I love to be able to [bring] many different skills to open up a mountain route. Whereas this was just one: it was about running across the country and just doing this one thing, day in and day out.

Was there something in particular you were hoping to accomplish?

The entire horse team ground to a halt on day 13—the worst day of weather during the expedition.

 I wanted to end my career as an explorer. When I first went to the Himalaya, I went there as a 22-year-old. My ambition at that time was that I wanted to climb Mount Everest and I wanted to become the youngest American to climb it—life to me is finite, and I always felt a sense of emergency about the mountains. In those 10 years of pioneering in the Himalaya, I had really clear, set, ambitious goals to open up new routes. To my knowledge, I’m still the youngest person to ever lead a successful expedition to the summit of Mount Everest on the north side. Then I moved on to new alpine routes, and I moved onto ski mountaineering and ski descents.

Annapurna mountains in sunrise light

To me, to truly understand the Himalaya, distance really was the last component to a career of opening up and understanding in every single way available to me what this mountain range was. And the thing I wanted to accomplish most was that understanding. This was the last true pillar of exploration that I thought was left for me in those mountains.

Instead of being out there in these cold, sterile, and pristine environments, the warmth of the relationships and the transformation of myself was the whole point of all of this. As I look back, all these other choices I’ve made were very clear-cut, whereas now I have a whole different vision for why I would return to the Himalaya, why I feel I can’t return to the Himalaya—I would just go back to see my friends and enjoy a nice time.

Is there anything else you want to mention about the Snowman Trek?

If someone’s thinking about doing the Snowman Trek, just buy the ticket, go over there, and start. Failure is so imminent and it’s such a valuable tool to learn how to do things the best way. You can read, you can talk to people, you can essentially composite or abstract everything that’s possible, but there is nothing like showing up on the doorstep of a major endeavor and failing miserably. I would recommend that people just never, ever get discouraged by the amounts of failures. You just don’t know where it’s going to lead, and you have to absolutely be OK failing, because all of these things at some point will add up to something and you just have to keep trying.