Cerro Piramidal del Potrero Escondido (5,386m) is located in the Central Andes, outside of Mendoza. On September 16, Lucas Amuchástegui, Juan Bautista Alonso, and Pablo Laumann (all Argentina) departed from Punta de Vacas to reach Río Chorrillos and begin their approach to the peak. The next day they trekked westward up the Quebrada de Chorrillos. On the third day they reached a 400m section of technical climbing that gains the upper valley. (This is approximatley two-thirds way up the valley.) They climbed three pitches and fixed ropes due to lack of time. On the fourth day they managed to climb through the rock band and make camp at ca 3,800m.
On the fifth day they continued gaining elevation up the valley and found a camp below the glacier under the south side of the peak at ca 4,200m. On day six they departed at 6:20 a.m. and began traversing a glacier (ranging from 30–60°) and passed a bergschrund. The section above contained deep snow and steepened to 75° on the final pitch. They reached the summit at 6:30 p.m and arrived safe at camp at 4:30 a.m. after getting lost on the descent.
In two days, the group hiked back out 40km to Punta de Vacas. They named the route Alto Guiso (500m, D 75° AI3 M3/4). The mountain had two previous ascents, one in 1965 from the west and one in 2005 from Quebrada del Potrero Escondido
Marcelo Scanu, Argentina