Monday, June 9, 2008

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Hubbard Glacier

United States of America
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Hubbard Glacier, located at Wrangell-St. Elias National Park near Yakutat, Alaska, is the largest calving glacier in North America. It is currently increasing in total mass and advancing across the entrance of 56-km-long (35-mile-long) Russell Fjord. These images show the potential environmental disruption that a fast glacial flow is capable of producing.

In 1986, the Hubbard Glacier blocked the Russell Fjord, endangering seals and porpoises by producing freshwater runoff that reduced the salinity of that body of water. Rising water levels also became a concern. By the time the ice dam eventually broke later that year, the water level of Russell Fjord had risen by 25 m (82 ft).

In late May or early June, 2002, Hubbard Glacier again pushed forward, blocking the seaward entrance to Russell Fiord and began to restrict the tidal exchange between Disenchantment Bay and Russell Fiord. By late July, the dam completely sealed off the lake. At 3 a.m. on August 14th, Russell Lake burst through the dam again becoming Russell Fjord. A one-hour peak discharge of 54,000 cubic meters of water per second (1.9 million cubic feet per second) is the second largest measured glacial lake outburst worldwide in historical times, exceeded only by the 1986 outburst from Russell Lake, which was about 105,000 cubic meters per second (3.7 million cubic feet per second). In comparison, the August 14 peak discharge was about 30 percent greater than the peak historic flow on the Mississippi River at Baton Rouge, La. View detailed information

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