Shadow Gully is a genuine mountain gully. It offers good climbing, being both steep and narrow in the upper reaches. The true line stays on the left-hand side of the gully, and hence the appropriate nomenclature, Shadow Gully. The main part of the gully itself, is sometimes referred to as Tregalan Couloir. Collectively, both Shadow Gully and Tregalan Couloir rise up to the south ridge of Snowdon, bisecting the extensive crag of Clogwyn Du.