Glacial Valleys

ECOSYSTEMS > INLAND OREGON > VALLEYS

During the Pleistocene Era (Earth's most recent ice age beginning about 2.6 million years ago and ending 11,700 years ago), glaciers covered huge parts of the Earth. As these walls of ice moved across the landscape, they carved out valleys similar to how a bulldozer might dig a trench. Because of the breadth and weight of glaciers, these valleys are wider and have flat bottoms with a contour similar to a “U”. As a result, these valleys may be alternately known as U-shaped valleys, trough valleys or glacial troughs. Glacial valleys often occur in mountainous areas of the world, including the Swiss Alps, Himalayas, Scottish Highlands, Scandinavia, New Zealand and Canada. In the United States, large glacial valleys can be found in Glacier and Yosemite National Parks.

Some glacial valleys may intersect with smaller, tributary valleys which are at a higher elevation. These are often referred to as "hanging valleys." Glacial valleys located along coastlines and are thus partially submerged are known as fjords. Fjords in the Pacific Northwest occur largely in Alaska, British Columbia and Washington State.