Hamish Brown comments on the name thus: “An Ruadh-stac is a grey hill, sometimes touched white by the sun but never red like its ruddy, bald headed neighbour (Maol Cheann-dearg).”[2] An Ruadh-stac has the classic triangular mountain shape formed by three steep ridges; the NE ridge is the least steep and the one usually used for ascent and descent by walkers.

This ridge drops to the 600-metre-high (2,000 ft) Bealach a’ Choire Ghairbh, which links the mountain to Maol Cheann-dearg, which stands 2 km to the north across Coire an Ruidh Staic.

The south ridge leads over the subsidiary top of Ruadh Stac Beag (758 metres) before descending towards Glen Carron over rough, boggy ground.

These crags rise over 400 metres from the shore of Loch Coire an Ruaidh-staic and have received the attention of rock climbers, with Tom Patey and Chris Bonington pioneering a 180-metre-long (590 ft) route in 1960.

[2] The lower slopes on the SE side of the mountain are composed of ice-polished slabs dotted with long flowing mounds of debris; this is fluted moraine, deposited from a glacier.