Denali National Park and Preserve Surging Glaciers

The Peters and the Muldrow Glaciers on the north side of Mt. McKinley are known to be surge-type glaciers, which means they get up and go suddenly after years of slugging along like other glaciers. The Muldrow Glacier last surged in 1956 and the Peters Glacier surged in 1986. These surges are known to last 1 to 2 years and may result in an advance of a glacier's terminus by several miles. During the most recent surge of Peters Glacier, the terminus advanced nearly 3 miles from July to the following May. The glacier may have moved 150 feet each day during part of the surge. Surging glaciers are one of the unsolved mysteries of glaciology. Many surge-type glaciers in Alaska, lie along or adjacent to the 500 mile-long Denali Fault. The Muldrow and Peters Glaciers are directly atop portions of this prominent break in the earth's crust, which arcs across Alaska and crosses the northern slopes of Mt. McKinley. Most recently, in 2000, surges occurred on the Tokositna Glacier within the park and the nearby Yanert Glacier. Today there is still visible evidence of the recent surges on these glaciers. Their formerly smooth surfaces are now slashed with huge crevasses, and the upper portions of the valleys are marked by a "bathtub" type ring caused by the sudden drop of the glacier's surface as the ice surged out below. Today if you stood on the upper part of the Yanert Glacier you would be 300 feet lower than you would have been prior to its surge!

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Featured Park
Rising above a scene rich with extraordinary wildlife, pristine lakes, and alpine terrain, the Teton Range stands monument to the people who fought to protect it. These are mountains of the imagination. Mountains that led to the creation of Grand Teton National Park where you can explore over two hundred miles of trails, float the Snake River or enjoy the serenity of this remarkable place.
Featured Wildlife
The pika is a close relative of the rabbits and hares, with two upper incisors on each side of the jaw, one behind the other. Being rock-gray in color, pikas are seldom seen until their shrill, metallic call reveals their presence.