Its cooling system relies mainly on underground pipes directly under the ground, covered with a layer of permafrost, explained site director Therez Söderberg. Above is a thin layer of artificial snow. It is brought in from a pile outside in January or February, just before the tunnel closes for the season, and is intended to last from the start of the next season, in early June, until its end seven or eight months later.
Visitors range from local students to U.S. World Cup cross-country teams. However, some locals still prefer to ski outdoors. “To some extent it still exists,” Söderberg said. “[The idea that] skiing is something you do outside.”
Soon it was time for me to experience the tunnel for myself. Equipped with skis and poles, I pushed open the door and entered a bright indoor room the size of a basketball court, with a snow-covered floor. At the end of the wall were the two tunnel mouths. The tunnel has two parallel runs of 1.3 km and can be skied in both directions, for a total distance of 2.6 km. The loop starts and ends in the lobby where I was. Here, the temperature is always -4°C. There is no wind or ice. The ski conditions are technically perfect.
After resident coach Rasmus Blom gave me feedback on my intermediate technique, I decided to venture into the loop alone. The 8m wide by 4m high concrete crescent was silent and ghostly around me. Except for my own ragged breathing and the tips of my ski poles hitting the snow and my skis sliding across it, all I could hear was the roof’s fan system. Sometimes the sounds of another skier betrayed their approach around a bend. Light streamed from the strips of light on the ceiling, interrupted by signs indicating emergency exits. But very quickly, all that vanished. As I continued the loop, falling into the familiar chain of motions necessary to propel myself forward on the skis, I found myself smiling.