Lasunayoc (5,936m, 13°16'6"S, 72°47'45"W) anchors the southeastern end of the Pumasillo group in the Cordillera Vilcabamba. Its normal route on the eastern glacial ramp and upper east face (including minor variations) has been repeated a handful of times since the first ascent in 1956 (AAJ 1957). Other major routes include the northwest face, climbed by a team from New Zealand (AAJ 1963), and northeast ridge, climbed by an Australian team (AAJ 1970). While climbing Padreyoc (5,771m) in 2021 (AAJ 2022), located to the southeast, I began thinking of a more direct route up Lasunayoc’s south side.

As the 2022 climbing season ended and October turned to November, it stayed very dry. I dreamed of getting on some ice and having a long, hard day in the mountains, as did Leo Rasalio (Peru), who has been steadily progressing to more difficult climbs. Leo grew up on a farm outside of Chinchero and has the natural ability to suffer, to weather the elements, and to keep going with the toughest of them.

We left Urubamba on November 11 and made the long drive to the village of Yanama (3,600m), nestled below the high peaks. We left the truck at a pasture just beyond Yanama Pass. From there, we shouldered 50-pound packs and followed cow trails through the tall grass. After a few hours, we reached a moraine ridge and followed it until it disappeared just south of Lasunayoc at a nice, flat outcropping. I set up camp while Leo explored access to the glacier below the south face. We went to sleep around 5 p.m.

We left the tent at 11:45 p.m. Within 40 minutes we were on the glacier, navigating crevasses in the direction of the lower south face. Although the moon was bright, huge cornices cast shadows over the wall. Starting in an alcove, we climbed steep, hard ice to the intersection with the south-southeast ridge, just below a large serac. Here, we could have kept going on the ridge, but rounding the shoulder to the east under the serac appeared faster. This required a tricky cornice traverse and then a pitch of steep water ice. A steep slope of loose snow brought us past the serac and eventually leveled off onto the upper glacier. Here, we took a long rest, enjoying the view of Veronica, Salkantay, and Humantay rising out of the misty valleys to the east.

The upper mountain seemed deceptively close, but a large bergschrund cut across the entire east face, and the climbing through the flats was slow in the deep, sun-heated snow. Thankfully, after joining the normal route on the upper east face, 60°–70° ice brought us to the upper ridge. A short walk along the broad summit ridge got us to the highest point at 1:40 p.m. (1,000m, TD WI4).

To descend, we made a deadman anchor from a snow stake to get past the steep upper face. We then plodded back across the glacier, sinking in every other step, toward the drop-off on the south wall. We belayed the traverse back under the serac, then prepared to rappel into blackness with headlamps. We did five rappels, three from V-threads and two from snow stakes, before reaching the glacier. We crawled into our tent again at 1:30 a.m. on the 14th, 25 hours after leaving.

Although Lasunayoc does not exceed 6,000m in height, it was more difficult than many 6,000m peaks I have climbed in this area and is every bit as epic as it looked from Padreyoc.

— Nathan Heald, Peru