Glaciers & Glacial Features

The Middle Teton glacier sits on the northeast flank of the Middle Teton, and is visible along the route to the Lower Saddle. Old snow from the previous winter appears white near the top and central parts of the glacier in early August; exposed ice appears gray. Snow lasting through the summer is known as firn. Firn lasting for several years becomes glacial ice.

NPS Photo

 

Every winter, hundreds of inches of snow blanket Grand Teton National Park. As spring approaches, snow melts, but even in the heat of summer, some snow remains in shaded or protected areas. As snow accumulates year after year, the compacted snow turns to ice. If an ice field grows large enough, the ice will flow and slide downhill under its own weight, forming a glacier. These ice bodies are a balance between accumulating winter snow and melting during warm summer days. Today, summer melt is outpacing winter gains, and the glaciers are retreating.

 

Three-dimensional diagram of a typical glacier highlighting various features.

Reproduced with permission from Creation of the Teton Landscape by J.D. Love, J.C. Reed, Jr., and K.L. Pierce, 2003

 

As glaciers flow, the ice carries rocky debris downslope. This material can be carried on the ice surface, trapped in the ice, or frozen to the base of the ice. The melting glacier deposits this debris at its terminus, creating ridges called moraines. The longer the terminus remains in the same place, the more debris accumulates. Large terminal moraines are visible below Teton and Schoolroom glaciers.

Another common glacial feature is a crevasse—a deep, V-shaped crack often visible in the uppermost layer of ice. Imagine bending a Snickers bar into an arch—the surface of the bar will crack, while the interior remains flexible. As a glacier flows, the brittle surface cracks as the more ductile base flows over uneven terrain or around a corner, resulting in crevasses. These open and close as the ice moves, so crevasse patterns constantly change.

 

(Left) Teton Glacier moraine is seen from above as the semi-circular sharp ridge of rocky material. The terminal moraine marks the greatest extent of the glacier in the late 1800s. The toe of the glacier is visible to the left of the moraine, although it is covered in debris.
(Right) Crevasses visible in the surface of Middle Teton Glacier.

NPS Photo, NPS/E. Baker

 

Today, there are up to 11 active glaciers in Grand Teton National Park. Ten glaciers have been previously named on U.S. Geological Survey maps: Teton, Middle Teton, Teepe, Schoolroom, Petersen, Falling Ice, Skillet, and East, Middle, and West Triple glaciers. In addition, there is another unnamed glacier near Glacier Peak. However, some of these glaciers may have lost so much ice volume that they have stopped flowing and are no longer active glaciers.

A few glaciers are easily visible from the roads in Grand Teton National Park, including Teton Glacier, Falling Ice Glacier, and Skillet Glacier. View the Teton Glacier from the Teton Glacier turnout on the Teton Park Road. Falling Ice and Skillet glaciers flank Mount Moran. View Falling Ice Glacier from the Mount Moran turnout and Skillet Glacier from Colter Bay area.

To learn more about glaciers, visit our page on current glacier monitoring in the park, and follow scientists on their annual Middle Teton Glacier survey in this short video. For more information on geologic topics, watch our geology podcasts and geology animation video.

Learn about glacier monitoring and other science in in the park in the "Dispatches from the Field" video series, on our YouTube channel.