Over a period of three weeks in December 2012 and January 2013, Anton Karnoup (Michigan,AAC) and I climbed a number of routes in Vallé Colorado, beneath the slopes of Mercedario (6,720m) in the Cordillera de la Ramada, approximately 100km north of Aconcagua. It was clear, sunny, and empty for the duration, and all snow slopes below 5,000m had turned to penitentes from the sun. We focused our attention on the cirque below the Negro Couloir(southwest of Cerro Negro), an area that contained multiple unclimbed, daylong ice routes with good rock on the west side, especially in chimneys. All routes lead either to the summit of Cerro Negro (5,600m) or to the smaller peak Negro Chico (5,200m), west of Cerro Negro.
The longest route we climbed took us two days round-trip. The route consisted of three large icefalls, separated by fields of penitentes and some rock. The first four pitches were all 55-60m (WI3–WI4 M3), and located in a chimney. The left side of the chimney ran with a waterfall most of the day, but to the right of it was a narrow runnel of ice, resembling Colorado’s famous Ames Ice Hose. The runnel stays in the shade all day, making for solid climbing, though it is generally hard to keep the belayer protected from falling ice. After four pitches, we spent the night on a flat scree platform (ca 4,600m).
The next day, we climbed 100m of fourth-class rock to reach the second icefall (55m, WI4), which ends on smooth rock with a thin crust of ice. Eventually, after several hundred meters of fighting penitentes, we reached a broad icefall at ca 4,900m (40m, WI5). The easier part of it was still overhanging. After this, several hours of snow and alpine ice led us to the distinct col along the ridge between Cerro Negro and Mercedario. From the col it was only a 30-minute scramble to the top of Negro Chico. We spent the night at the col and then descended to the west, first along the main ridge, then south down penitente slopes to a broad scree shoulder. At the far end of it, a couloir led us left (east), the top of which we marked with a cairn. This descent route did not require a single rappel and can be used for other routes leading to Negro Chico. We named the route after Boris Avdeev, a great rock climber and friend who died skiing the Dana Couloir in Yosemite: Boris Avdeev Route (1,000m, WI5 M3).
We also climbed several other routes nearby: Chapaev de Los Andes (3 pitches, WI4 M3), an alternative to the start of Negro Couloir; Pecho Frio (5 pitches, WI3+), and the magnificent Cascada del Aguilas (5 pitches, WI5). Anibal Maturano, author of the local guidebook, believes that all routes were first ascents except for Cascada del Aguilas, which was climbed by Argentineans Javier Giuliani and Fabrizio Oieni in 2011. All routes require 60m ropes, a handful of ice screws, and small rock protection.