Nevado Huayllaco (5,460m, also spelled Huaiyacu, approximately 9°50'4.21"S, 77°11'21.61"W) was first ascended in 1963 by Domingo Giobbi (Italy/Brazil) and the brothers Eugenio and Macario Angeles (Peru), who called it Raria Este; they likely ascended the southeast ridge. In those years, Giobbi was very active in the Cordilera Blanca and surrounding mountains. [Editor’s note: Huayllaco also appears to have been climbed in 1972 from the saddle to the west (see AAJ 1975).] Huayllaco is located in the far southern Cordillera Blanca, which sees fewer visitors than the zones to the north. So, the July 25 attempt by Marcelo Motta Delvaux (Brazil) and Julieta Ferreri (Argentina) may have been the only one for decades.
They approached the mountain via Quebrada Huayllaco, camping at Laguna Verdecocha (4,650m). From there, they reached the southwest glacier, which provides access to the col between Huayllaco and Nevado Raria (5,576m). They then trended right and climbed directly up the south side of Huayllaco, a short, beautiful face (60–70°) that reaches the southeast ridge. Near the ridge, they encountered a section with powder snow, dangerous cornices, and no protection, just to the right of a prominent rock band; they finished their climb there, approximately 10m short of the southeast ridge and a considerable distance from the summit.
– Marcelo Scanu, Argentina
A video of the team’s prior June ascent of nearby Raria from Laguna Verdecocha provides a good overview of the area. Raria is to the west of Huayllaco.