Glacier National Park, Montana

Going To The Sun Road
Trip Day Nine: June 20, 2000

Jackson Glacier Overlook

Text from plaque above:
     Avalanches take only seconds to alter these slopes dramatically. when an avalanche releases, tons of snow hurtle down the mountainside with tremendous force, snapping large trees like twigs and opening a braad swath through the forest.
     As the sanow of winter recede, plant and animal species adapted to more open, sunny conditions, quickly colonize these avalanche chutes. As it has for millions of years, the power of snow and ice continues to shape this mountain landscape.
     Attracted by the diversity of plants and animals found there, grizzly bears search for food inan avalanche chute.
     From a distance avalanche chutes may appear stripped of vegetation. But berry bushes and flexible shrubs over six feet high dominate these sunlit openings.

Shrinking Glaciers

Today Jackson Glacier is barely visible among the peaks. In the mid-19th century it extended much farther down the valley and connected with neighboring Blackfoot Glacier in one continuous mass of ice.

Tree-ring studies, conducted in the forest at the head of the valley, indicate the ice began its retreat in 1860. Lite most glaciers within the park, it continues to shrink.

A glacial landscape can evolve with startling speed. Return in a few years, and you may witness newly exposed ground that was buried under ice for centuries—or the glacier may be advancing again.

Tens of thousands of pounds of ice compress the bottom layers of a glacier, deforming the ice and causing it to slowly flow. Surface ice, however, remains brittle, creating spectacular crevassing as the glacier flows over the rocky substrate.

Page last updated July 29, 2000.