Investigation into debris flow activity was undertaken in Glen Docherty. Both the historical and recent records of debris flow activity in the glen are outlined. While the glen’s psammites have a low debris flow spatial density relative to that recorded in areas underlain by other rock types, the volumes involved are high. Debris flow gully propagation, as it occurs on both vegetated and non-vegetated talus, is examined. Evidence from recent events calls into question whether debris flows are effective agents of flow channel scour. Progressive slope failure is proposed as a possible mechanism in gully propagation. Fluvial activity was also found to play an important role in debris flow processes including gully development.