The only serious multi-day in the Chaltén valley and one of the most technically demanding trekking circuits in South America. 66km total, two tyrolean traverses over the glacial Río Túnel, two high passes exposed to legendary Patagonian wind (routinely 100–160 km/h at Paso del Viento), a 1,342m descent to Lago Viedma, and a boat pickup at the end. Self-guided is LEGAL via free APN online permit — but genuinely requires rope/harness skills and self-rescue competence. Do not attempt as your first self-supported trek.
Distance
55.3 km
Max elevation
1,550m (Paso del Viento)
Duration
4 days
Safety classification
DifficultyMountaineering
GuideGuide required (safety)
Gear
Technical gear
OfficialYes
MaintainedNo
Season
Summer only (roughly October–April); APN treats it as a remote-area itinerary with per-trip mandatory registration, and rates days 2–3 'High' difficulty with an explicit 'APN don't recommend this trail in windy days'. NOT safe: any windy day (Paso del Viento / Paso Huemul), May–September winter, and — status warning — the full circuit was CLOSED in January 2026 after the Cerro Huemul forest fire (fire perimeter ~704 ha per APN's 17 Jan 2026 inspection, not ~140 ha); APN's last verified authorization (17 Jan 2026) enabled only Laguna Toro–Paso del Viento out-and-back, with Paso del Viento–Bahía Témpanos–Bahía Túnel still closed. Confirm current authorization with APN before selling or walking the full loop (Ceferino Fonzo Visitor Center, El Chaltén — informeszonanorte@apn.gob.ar, tel (02962) 493004).
Hazards
▲Two tyrolean (zip-line) cable crossings of Río Túnel — APN: never clip to the steel wire with an aluminium carabiner; 'previous skills in using this kind of installations are indispensable'; fording instead is exposed to rising glacial water ('at your return the level of the river could be deeper')
▲Túnel Glacier crossing: APN warns 'getting in and getting out of the glacier is extremely dangerous' — unstable moraine, falling rocks; the access points shift periodically
▲Violent wind at Paso del Viento (~1,400 m) and especially Paso Huemul — APN does not recommend these stages on windy days
▲Unmaintained, sparsely marked route: APN's own characterization is 'trails without maintenance', 'not enough signs'; marker sticks can be fallen or overgrown
▲River fords (Río Paula and others) — watch the level
▲Extreme remoteness: APN warns of 'difficulties in helping you out in case of emergency' and starts search and rescue only 48 h after your declared return time
▲Fire-damaged terrain from the January 2026 Cerro Huemul fire
▲Camping forbidden at Paso Huemul; only Toro, Refugio Paso del Viento and Bahía Témpanos sites
APN's own circuit presentation: 4 days/3 nights, 65 km, ~1,000 m max gain, 26 h walking; days 2–3 rated 'High'. Required per-trip online/in-person registration (personal, sworn declaration) plus APN gear list: harness, 2 locking carabiners and safety line per person; steel carabiner, 35 m cord, topo map and stove per group. Crampons are 'not necessary in usual conditions' on the Túnel glacier, but this is glacier travel with fixed-cable crossings, not a trek. APN permits unguided parties with mountaineering experience and demands full self-sufficiency — anyone without real alpine experience should treat a licensed guide as required. Danger/view-only for jtreks purposes until APN confirms the full circuit is re-enabled post-fire.
Verified 2026-08-23Official source ↗Administración de Parques Nacionales (Argentina)
