Atlas › Sierra de Guara - Balced / Furco
Oscuros del Balcez
not verifiedpermit verified 2026-08-19
ACA 3C2 II
High flood risk
Bierge, Huesca
A dark slotted swim through the Rio Isuala under the Balcez cliffs: the narrows are the draw, with several long dark pools you swim head-down between vertical walls.
Despite the popularity, this canyon is fully committing once you are in the slot. The cold water and consistent narrows mean a full wetsuit is non-negotiable. Rangers occasionally collect visitor data at the put-in. Duplicate row balcez-oscuros-del merged 2026-08-21 (EXECUTE-PLAN.md 5.4): a thin CSV-import shell for the same canyon carrying no prose, no sources and no enrichment. Its bare grade '3C' is a truncation of the grade this record's own tech prose states in full, so the fuller form was set instead.
Logistics
| Manager | Parque Natural de la Sierra y los Cañones de Guara |
|---|---|
| Permit | No permit or registration required for individuals. Group cap 10 persons (excluding guide) per Decreto 204/2014 for the Balces section. Minimum 10 minutes between groups. Neoprene mandatory. |
| Distance | 0.9 |
| Elevation | ~197 ft gain on exit |
| Time | 3-3.5 hr |
| Technical | Ropewiki rates 3C2 II (v2a5 III). Longest rappel 33 ft, sustained narrows with rappels, jumps, and several long narrow dark swims through the slot section on the Rio Isuala. Anchors are bolted and maintained, done by multiple groups daily in summer. |
| Season | Spring through fall, avoid winter |
| Flood risk | High. Long narrow slot with no easy escape; cold water and strainers possible at high flow. |
| Vehicle access | 2WD passenger car |
| Crowd | Guided groups present in season but progress through the canyon is fast |
| Coordinates | 42.2378, -0.0482 |
Sources
- group size rule: https://montanaregulada.org/en/espacio-protegido/parque-natural-de-la-sierra-y-los-canones-de-guara
- park regulation: https://www.aragon.es/-/parque-natural-de-la-sierra-y-canones-de-guara
- ropewiki: https://ropewiki.com/Balcez_(Oscuros_del)
- heroPhoto: https://commons.wikimedia.org/wiki/File:R%C3%ADo_Isuala,_depuis_la_Sierra_de_Balced,_2009_(DSCF0028).JPG
- permit: https://www.aragon.es/-/parque-natural-de-la-sierra-y-canones-de-guara
- canyoneering grade: own tech field, stated explicitly; see notes for the merge