On January 16, 2021, Sebastián Martino and Mauro Schmiedt (both Argentina) began their approach to Cerro El Moño (4,699m; 34°47'53.8”S, 70°14'53.6"W) in Mendoza Province, and reached Refugio Soler that day. The next day, they crossed the Río Atuel and entered the Valle de las Lágrimas, close to the site of a 1972 Uruguayan plane crash made famous in the book Alive. They crossed the river, passing El Barroso, and, after eight hours, made camp at 2,600m.

On the 18th, they ascended a gully and ridge to reach a hanging glacial valley below Cerro El Moño, which was believed to be unclimbed. They made camp at 3,800m. That night, they heard heavy rockfall but did not find out until days later that a magnitude 6.4 earthquake in nearby San Juan Province was the cause. On the 19th, they departed camp at 6:30 a.m., ascending a broad apron of snow penitentes on the east slopes to reach a steeper couloir, which seems to provide the only access to the rocky summit plateau. By 10:30 the pair had reached the summit (ca 4,700m GPS) atop the Argentina-Chile border.

On the 20th they descended to Refugio Soler and rested one day before trekking to a camp below Risco Plateado (4,999m; 34°55'4.77"S, 69°59'34.78"W), located 25km to the southeast. Although there are no recorded ascents of this peak, it may have been climbed in modern times from the south and likely was climbed in Incan times.

From the Atuel River valley, north of Risco Plateado and south of Cerro Sosneado (5,189m), they crossed the Atuel River and then hiked southwest for 8km to reach a camp at 3,800m below the peak’s northeast ridge. On the 23rd, they continued up the ridge, wrapping around a subsummit onto the glaciated saddle and then the summit (about 4km in all). They found a wool doll on the summit, indicating the Inca likely reached this summit first. Interesting pre-Columbian discoveries have been made on Cerro Sosneado, and the area may have been one of the southernmost high-mountain sanctuaries for the Inca.

— Marcelo Scanu, Argentina