Slot Canyon Atlas

AtlasSierra de Guara - Balced / Furco

Oscuros del Balcez

verified Ungraded 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.

Logistics

ManagerParque Natural de la Sierra y los CaƱones de Guara
PermitNo 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.
Distance0.9
Elevation~197 ft gain on exit
Time3-3.5 hr
TechnicalRopewiki 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.
SeasonSpring through fall, avoid winter
Flood riskHigh. Long narrow slot with no easy escape; cold water and strainers possible at high flow.
Vehicle access2WD passenger car
CrowdGuided groups present in season but progress through the canyon is fast
Coordinates42.2378, -0.0482

Sources