Title Bar: Illustrated Glossary of Alpine Glacial 
	  Landforms | Home   | Glossary   | Exercise |


    Erosional Landforms
    Giant stair steps
    Glacial trough
    Hanging valley
    Paternoster lakes
    U-shaped valley

    Depositional Landforms
    End moraine
    Ground moraine
    Lateral moraine
    Medial moraine

    Ice Features
    Cirque glacier
    Valley glacier
    Ice fall

A semi-circular or amphitheater-shaped bedrock feature created as glaciers erode back into a mountain. This is where the snow and ice forming the glacier first accumulates; it is the "headwaters" of a glacier.
Photo: cirque

Topographic map: cirque

Photo: R. Schukar. Used with permission.

In the photo you are looking at the back wall of the cirque occupied by Lake Ellen Wilson in Glacier National Park. A red line on the topographic map marks the back wall of the cirque. The photo was taken approximately from where the camera is located on the map, looking toward the northeast. Just a small portion of Lake Ellen Wilson shows in the foreground of the photo. The headwall of the cirque is quite steep, although this is not readily apparent from the photograph. The closely spaced contour lines on the topographic map, however, clearly show the steep back wall of the cirque. The semi-circular shape is evident in both the photo and on the topographic map. Lake Ellen Wilson is an example of a tarn. Although no glacier exists here today, at one time a glacier formed here and flowed down the valley to the southwest.

The topographic map shows a waterfall just southwest of Lake Ellen Wilson and northeast of Lincoln Lake. The contour lines crossing the waterfall are similar in appearance to the contour lines defining the cirque that Lake Ellen Wilson sits in: they are semi-circular in shape and closely spaced. Although the shape and spacing of these contour lines makes this feature appear like a cirque, it is not a cirque. There is just one cirque for a particular glacier and the cirque is located where the glacier begins. To identify a cirque for a glacier that still exists, look at the highest elevation where the glacier starts. To identify a cirque where a glacier no longer exists, follow the river currently occupying the glacial trough upstream to where the river starts and that is where you should find a cirque.

| More Examples of Cirques |

| Home | Glossary | Exercise |

| Virtual Geography Department Project | Physical Geography Working Group |
All commercial rights reserved. Copyright 2010 by Karen A. Lemke. Earlier copyright 2002 by Karen A. Lemke, and 1998 by Karen A. Lemke and Linda Freeman.
Last updated June 2010 KAL.