Don Bosco, South Face Ascent and Ski Descent, 1991. Italian Tone Valeruz is well known for his extreme ski descents. On January 14, 1991, he made a new route solo on the south face of Don Bosco (2515 meters, 8251 feet), taking only three hours to climb the 600 meters from the glacier to the summit. Part of the ascent was on 80° ice. He descended some of the route on skis, but was forced to climb down a part of it on foot.