Earth  ID: 10982

Rapid Retreat

Story by Adam P. Voiland | Visualizations by Robert Simmon Released on June 14, 2012
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Satellites have observed one of the fastest-changing glaciers in the world withdraw into the mountains of southeastern Alaska.
Columbia Glacier descends from an ice field 10,000 feet above sea level, through the flanks of Alaska's Chugach Mountains and into a narrow inlet. Since 1980, the glacier has lost about half of its thickness and volume, while the front where the glacier's ice meets open water—called the terminus—has retreated more than 12 miles. Climate change may have helped nudge the terminus off an underwater anchor of rock and debris that stabilized the ice for many years. Once it lost that footing, the lack of friction between ice and bedrock has driven a rapid loss of ice from the glacier to Columbia Bay. A time-lapse video of false-color images captured by USGS-NASA Landsat satellites shows how the glacier and the surrounding landscape changed between 1986 and 2011. Watch ice give way to ocean and bedrock become exposed as Columbia Glacier retreats.
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Snow and ice are seen as bright blue, while vegetation appears green and bedrock brown. Gray stripes on the glacier surface represent rocky debris.
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By 2011, the terminus had moved back more than 12 miles, essentially splitting Columbia into two glaciers with distinct fronts.
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Floating icebergs that calved from the edge of the glacier fill Columbia Bay.
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Standing 100 feet above the bay, a tower of ice in the process of becoming an iceberg separates from Columbia Glacier's terminus.
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This aerial view from 1969 shows Columbia Glacier's ice filling the inlet.
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By 2004, water had replaced much of the ice.
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The terminus was approaching the foot of the Chugach Mountains when this photo was taken in 2011.

For More Information

NASA Earth Observatory

Story Credits

Lead Visualizer/Animator:
Robert Simmon (Sigma Space Corporation)

Lead Writer:
Adam P. Voiland (Sigma Space Corporation)

Please give credit for this item to:
NASA Earth Observatory
Floating icebergs photo courtesy of Jon Von Atta, copyright 2008
Calving front photo courtesy of U.S. Army Engineer Research & Development Center
1969 aerial photo courtesy of National Snow and Ice Data Center
2004 aerial photo courtesy of National Snow and Ice Data Center/W.T. Pfeffer
2011 glacier terminus photo courtesy of USGS/Shad O'Neel

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Keywords:
SVS >> App
NASA Science >> Earth