To the north-east the fell is separated from Skiddaw by Carlside Col (2,345 ft), a depression that contains Carlside Tarn, the only standing water found at any altitude in the Skiddaw group. Very shallow and frequently dry in summer, the tarn has no plant life. Set in a particularly windy location, the slight retaining bank at the south-eastern edge may be in danger of erosion. The Skiddaw side of the col is a rough scree slope while the Carl Side slope is gentler and grassed.