AbstractThe erosional morphology in the vicinity of the Main Divide of the Southern Alps, and Fiordland, New Zealand, appears to be a product of the interaction between Alpine Fault‐induced tectonic processes, rock mass strength of the uplifted and eroded bedrock, and the processes acting to denude the developing mountain landscape. The magnitude of the effects of glacial erosion on the landscape is directly controlled by the size and physical properties of the glaciers, whilst the form of the trough is a direct consequence of the rock mass strength (RMS) properties of the slope rock. Realistic models of development of the cross‐profile shape of glacial valleys must take into consideration the RMS properties of the eroded substr