It's a route that you cannot climb in summer and that you don't really want to climb in winter: Helmcken Falls. But ice-climber Will Gadd knows that the technically challenging mixed route on the rear wall of the 141-metre waterfall can only be mastered at sub-zero temperatures, because that's when the loose rock is literally frozen up by the spray. However, what works for the route doesn't necessarily help the athlete. The centimetre-thick layer of ice which Will has to remove from his safety rope at regular intervals doesn't really make it easier for him to warm up to the route.