Monte San Lorenzo

PeaksSanta Cruz,Argentina

Patagonia's second-highest summit and one of its least climbed, on the Argentine–Chilean border, guarded by weather so fierce fog can close the top within minutes.

September·Edge of season

Sep–Nov

Spring is the ski-mountaineering window: deep, stable snow and relatively light winds draw climbers onto the glaciers while the walking trails still lie buried. Days lengthen fast, and by November the trailhead ranch reopens for the season.

Year-round Patagonia's second-highest peak, its three glaciers and its valleys of lenga beech forest are here year-round; summer, November to March, is the season for walking those near-empty valleys below.

Monte San Lorenzo rises 3,706 metres on the Argentine–Chilean border, the second-highest summit in all of Patagonia and one of the least climbed. Only Monte San Valentín stands higher. Yet while nearer peaks like Fitz Roy draw crowds, San Lorenzo is guarded by some of the fiercest weather in the range: relentless wind, heavy snowfall and fog that can close over the summit in minutes. Three great glaciers spill from its flanks, two on the Argentine side and one on the Chilean, and the mountain answers to a different name on each side of the line. Its first ascent was the work of a missionary priest rather than a mountaineering expedition, and success is still rare. Few travellers come this far, and those who do trade Patagonia's busy trails for wind, silence and space. Southern beech forests of lenga and ñire climb the lower valleys, glacial streams run cold over the stones, and the endangered huemul deer still shelters in the woods at the mountain's feet. At dawn the summit flushes rose and copper before the wind rises to sweep the steppe; after dark, with no town for miles, the sky comes out free of light pollution. The Argentine approach begins at the turquoise lakes Posadas and Pueyrredón, and the Chilean side is reached through the small town of Cochrane. There are no services at the foot of the mountain, so everything is carried in. For mountaineers this is a serious, technical objective. For everyone else, the valleys below are one of the last places in Patagonia where you can walk for days and meet almost no one.

Worth knowing

Good to know

Come between November and March, the Patagonian summer — the only stretch with workable weather, though wind and sudden storms never fully let go, so keep plans loose.
Stock up in Perito Moreno or Cochrane — the Chilean approach then runs through a family ranch that owns the base-camp valley, and its track is open only for the summer season.
Build in spare days and pack for four seasons — fog and gale can pin you down for a day here, so a rigid, fixed-date itinerary almost always breaks.

Things to do

1
Walk the lenga valleys below the peak
Follow the trails that thread the southern beech forest and glacial streams toward the mountain's base, where the loudest sound is the wind. This is Patagonia at its emptiest — you can walk for hours and cross no one. In late spring and early summer the valleys below the snowline green up and wildflowers open across the steppe, the gentlest season to be here between retreating snow and the summer wind.
2
Attempt one of Patagonia's most feared summits
For experienced mountaineers, San Lorenzo is a serious, technical climb through crevassed glaciers and granite towers, defended by weather that turns many parties back. The standard line, the route De Agostini found after three summers of looking, starts from a camp north of the mountain and swings all the way round to climb the western slope.
3
Hold the pre-dawn cold at the De Agostini base camp
Hike the long approach to the De Agostini base camp below the hanging glaciers, then wait out the dark, freezing hours before sunrise. When the sun clears the steppe it strikes the high face first, lighting the peak while the valleys around you stay in shadow. The same reward comes when a Patagonian storm finally tears apart and low sun pours violet and gold across the wet granite and ice.

Watch

Nearby

109 km