Cardinal Obsession

Gilles Sierro stood on the summit of the Dent Blanche and peered down into the void he had just climbed up alone, the wildly steep and terrifyingly exposed East wall. It would be his third time skiing off the top of the great peak, having already accomplished descents of the mountain's West-Southwest Couloir and South Ridge. It was 9 am on April 22, 2015, but despite the early hour and season, and the mountain's dizzying height of 4,357 meters, the sun had already begun to loosen the snow from its tenuous grip on the underlying ice and rock. The time to ski was now. Born and raised in Hérémence in the Val d'Hérens, giant summits like the Dent Blanche have been Gilles Sierro's lifelong backyard playground.

And as an IFMGA mountain guide, they are also his office. He has summited the Dent Blanche more than thirty times, often with clients, and his résumé of impressive steep ski descents in the region grows longer each season. So it was no surprise when director/photographer David Carlier tapped Sierro to represent the Hérens district in his new film, 13 Faces du Valais. And what better place to showcase Sierro's steep skiing abilities than on the crown jewel of the Val d'Hérens, the Dent Blanche? A precipitous pyramid, the Dent Blanche is the seventh highest summit in the Alps, with four prominent ridges radiating outward in close adherence to the cardinal directions. Seen from directly overhead, the mountain forms a cross.

Between these four main ridges, magnificently steep walls of rock and ice, just barely within the realm of skiable slope angle, fall away to the glaciers below. Only a handful of people has ever made ski tracks on this peak. Dédé Anzevui was the first to ski the South Ridge and the East Face, using a helicopter to reach the summit in both cases. Sierro's legacy with skiing the Dent Blanche began by repeating Anzevui's South Ridge route, before authoring the spectacular Swiss Fall Line route down the peak's West-Southwest Couloir with two friends in June of 2013. Sierro made these two descents under his own power, making the long approach hike and climbing the entirety of each route.

But in 2015 on the East Face, because of the requirements of production for the film 13 Faces du Valais, and the fickle timing involved in skiing a highly sun-exposed east-southeast aspect, Sierro and his team employed a different set of tactics. After a very dry winter, an actively snowy weather pattern finally developed in late March and early April, coating the high peaks in snow. Conditions for an attempt on the face were deemed acceptable, and Sierro, Carlier and two cameramen were helicoptered to a bivouac on the ice cliff below the East Face where they camped for the night. The next morning, after the team documented his preparations and departure, Sierro began climbing the face alone.

As with the other big lines Sierro has skied, climbing the line was an indispensable tactic, giving him the chance to test the snow, feel for rocks and ice hidden under the surface, and memorize all of this information in preparation for skiing back down. "My main safety concern was actually the least-steep part of the route near our bivouac. This is the most avalanche-prone part of the route, so it was important to take a safe line across it, as quickly as possible," said Sierro. Once through this section and onto the steep upper face, Sierro was moving fast. After about two hours of climbing, Sierro stepped onto the summit of the Dent Blanche, preparing his equipment for the descent.

After shooting off a text to his girlfriend, he gave a brief interview and was rigged with a GoPro for the filming. "Like with any big descent I do, I was pretty relaxed. I was just enjoying the view and not over-thinking the skiing ahead," recalled Sierro. "I was concerned for sure, but not worried. Skiing is supposed to be fun, and I wouldn't like it if I was shit-scared all the time. If I've made it to the top, I've already climbed the route, inspected the terrain and conditions first-hand, and am confident that I can do it." He dropped in and found dry powder snow on the first 50 meters. The steepest skiing came in the first section, with the slope reaching around 58 degrees.

As he descended, the snow transitioned from powder into heavy, unpredictable spring snow. The technical crux came high on the route, where it entered a deep, V-shaped gully between two snow flutes. "I would make two, maybe three turns on one side of the gully, absorb the gutter as I crossed to the other side, and make turns on the other half," Sierro explained. Due to the snow surface being warmer than when he climbed in the colder morning hours, Sierro uncovered unexpected patches of ice on three separate turns. After navigating the difficulties of the upper face, he quickly crossed the exposed exit ramps, returning to the relative safety of the ice cliff bivouac.

And just like that, Sierro had ticked off the third quadrant on the great compass of the Dent Blanche. From the icefall, the helicopter took the entire film team back to the Sion heliport in the Rhône Valley. The historic heat wave that affected Europe in the spring and summer of 2015 began that same day, effectively ending steep skiing season for the rest of the year. Observers of steep skiing in the Alps may notice that the North Face of the peak, despite how unlikely it may appear, remains without ski tracks. And also that Sierro has three of the four sides of the mountain under his belt already. So is there a line up there? Can it be done? "Who knows," says Sierro.

"It's all about finding the right combination of magical conditions, free time, having the drive to go for it, and being in a good place in your head. There's a reason it hasn't been skied. But you know me."