If you look at, or map and quantify, subglacial bedforms it is obvious that they are not just individual features (e.g. a drumlin) but are part of a ... that can amplify small disturbances in the flow ...

Glaciers can form distinct landforms through erosion of the landscape such as corries. Glaciers also deposit material to form unique landforms such as drumlins. Glaciated landscapes are a source ...