Sperry Glacier sits in a northwest-facing cirque. Take a look at the 1;100,000 topographic map to orient yourself. The 1:24,000 topographic map will give you a more detailed view of the glacier. Leave both of these extra windows open until you are finished with the two activities listed below.
The photo above shows some banding on the surface of the glacier. This photo and the one below also show some crevasses or cracks in the glacier. These are indications that the glacier is still flowing.
Rocks on the surface may be used to monitor the rate of movement. Johnson (1980) presented some rates of flow for Sperry Glacier based on rock movement. The rocks provided a 20 year record of movement from 1949-1969 and revealed an average annual movement rate of 11-28 feet per year (Johnson, 1980). The rocks also revealed that movement along the western edge of the glacier was greater than in the central part of the glacier (Johnson, 1980).

The history of the glaciers in Glacier National Park must often be inferred from indirect evidence. For Sperry Glacier, observations exist dating back to 1901, at which time the Chief Mountain quadrangle was being mapped (Johnson, 1980). The observations and data collected since that time have been sporadic, but do provide a picture of glacial activity. Information helpful for deciphering the past history of glaciers includes old and current photos, notes from field mapping expeditions, existing landform assemblages, tree ring studies, soil profile studies, and dating of volcanic ash (if present). Two activities are listed below in which you will use existing data to interpret the history and landscape of Sperry Glacier.

Size of Sperry Glacier

Landforms Associated with Sperry Glacier

When you are finished with these two activities, you should close any extra windows you have open before moving on.

Created February 26, 1999 by Karen A. Lemke (klemke@uwsp.edu). Last updated March 15, 1999 by KAL.
The URL for this page is http:/www.uwsp.edu/geo/faculty/lemke/gnp_vft/stops/stop3.html