On the north side of Mt. Hesperus there is a small active glacier. This glacier is unusual in that the entire glacial system from hanging wall to terminus can be observed in one photograph and the glacier displays most of the major physiographic features formed in this environment.
The source area of the glacier is a rounded bowl, referred to as a cirque. The cirque has near vertical headwalls on three sides but is flat or slightly inclined at the mouth. Prior to glaciation the cirque was probably nothing more than a gentle depression on the north facing mountain slope. Snow accumulated in this depression and as the glacier evolved, the movement of the ice carved out the circular shape.
From the cirque the ice flows into a valley where it carved out a U-shaped valley with steep sides and a flat bottom. This shape is distinguished from a V-shaped valley carved out by a river or stream.
The glacier in this photo is receding, as are nearly all glaciers in North America. As the glacier melts a huge debris pile is left behind along the sides of the glacier (lateral moraine) and at its terminus (terminal moraine). The height of the moraine defines the maximum height and advance of the glacier.
| The major physiographic features associated with a mountain glacier are displayed in this small glacier on the north face of Mt. Hesperus. This photo was taken in 1980. The glacier is now gone. |