Our adventure begins at the train station in Randa in the Mattertal. From there, the grueling but beautiful ascent leads up to the Weisshorn Hut (2,932 m). At the hut, my guest and I enjoy the fantastic panoramic view over coffee and cake. After an early dinner at 6:00 p.m., we go to bed early, as we have to get up at 2:00 a.m.

Right on time at 2:15 a.m., we set off roped together into the darkness. The first challenge is finding our way at the so-called “Wasserloch”—a couloir that we have to traverse in a zigzag pattern. In the glow of our headlamps, a neighboring gully looks deceptively similar to the correct route. As a mountain guide, I know the pitfalls of the terrain: I find the right starting point right away, and the rocky ridge that follows clearly marks the path to our breakfast spot from there on.

A good 2.5 hours after setting out, we arrive at the breakfast spot, the starting point for the famous east ridge of the Weisshorn. We climb the ridge in the dark until dawn breaks on the summit slope. Here we strap on our crampons and make swift progress over hard firn, ice, and rock, climbing the final 400 meters of elevation. Shortly after 7:00 a.m., we stand on the 4,505-meter-high summit, overjoyed.

The breather is brief, because we’re facing an enormous physical challenge: a steep 3,100-meter descent in one go all the way to the train station in Randa—a real test of endurance for our knees. But we manage that too, and by early afternoon we’re already sitting back and relaxing on the train.

One of Switzerland’s most impressive and challenging alpine tours—one you’ll remember forever.