Pumasillo, Cordillera Vilcabamba. The Cambridge (England) Andean Expedition, under the leadership of John H. Longland and Simon G. McH. Clark, was in the Cordillera Vilcabamba from mid-June to mid-August. Knowing from the British and American parties of 1956 that approaches to Pumasillo (about 20,200 feet) from the west and from the east were pretty hopeless, we tried to come at the peak from the north and to work out a muleable route to its base. After three weeks we found that the northern approach was no good, but that we could enter the Pumasillo basin from the south through a gorge that had discouraged previous parties. On July 13, 1957 we set up Base Camp at 14,750 feet in the basin at the foot of the west ridge, probably the only safe route with current techniques. Advanced Base was below the West Buttress at 16,250 feet, Camp I at the top of the west glacier icefall at 18,000 feet, and Camp II above the west ridge ice-buttress at 18,700 feet. The icefall was difficult and complex but seemed generally stable; most of it is safe from the threat of avalanches from higher up. The ice buttress was very difficult, being steep and requiring artificial aid for an overhanging section with dangerous vertical unconsolidated snow above. We had the whole 700 feet protected with fixed ropes, many pitons, stirrups, and three-foot aluminum stakes; this was the crux of the climb. From there to 500 feet below the summit, the west ridge was straightforward, steep ridge-work. We were then forced onto the south face, where the snow is always bad in the Andes, climbed a hard 60-foot ice wall and joined the summit ridge about 400 feet from the top. The ridge was heavily corniced and very complicated by towers as well. Before the summit we abseiled into a 40-foot gap, made the top, and then had to climb laboriously back up the rope. It is just as well that the ice buttress and final ridge were not any harder, but it was an enjoyable and difficult peak and well worth getting the whole party to the top. On July 23, Mike Gravina and Clark reached the highest point. On the 25th Harry Carslake and I climbed to the summit, followed the next day by Kim Meldrum, Colin Darbyshire, and Ronnie Wathen. We also climbed three 5000-meter peaks (above 16,400 feet) north and west of Pumasillo and mapped some of the west side of the range.
John H. Longland, Cambridge University Mountaineering Club