November 25, 2009

Grasshopper Glacier, Montana-nearly gone

Posted by Mauri Pelto

Grasshopper Glacier, the largest is located about 19 km. north of Cook, Montana within Custer National Forest. The glacier on Iceberg Peak occupies a north facing cirque at nearly 3300 m. (11,000 ft.). In 1940, it was about 1.6 km. wide and on its northwest side terminated in a 15-m. cliff. In 1966, seen below, the glacier had an area of 0.42 square kilometers. The name of the glacier is derived from the myriads of grasshoppers that were embedded in the ice. These grasshoppers either were downed by sudden storms or were carried over the glacier by strong air currents, where the cold forced them onto the ice surface. The grasshoppers are an extinct type of Rocky Mountain grasshoppper Melanoplus spretus. They perished here, were buried by new snow and preserved. At the time the glacier ended in a small lake. Progressively the glacier has retreated. By 1966 it was 0.6 km long, in 1994, seen below, 0.36 km long and in 2006 0.27 km long.

In 2005 this glacier has ceased to exist as a glacier, there are a few remnant perennial snow and ice patches the largest with an area of 0.05 km2. In the majority of recent summers the glacier has lost all of its snowcover. Glacier survival is dependent on consistent accumulation retained on the glacier each summer, this glacier will not survive. The glacier has continued its rapid recession and the further segmentation into small disconnected segments, heralds the end of an active glacier. We do have a gorgeous new alpine lake in its place. Notice the basin is still largely devoid of plant life and the surface still has the color of newly exposed-deposited sediments.