Alaskan History
Glacial Lake Ahtna Reseach suggests Glacial Lake Ahtna may have been a serial generator of some of Earth's largest freshwater floods. Maps and photographs are from the United States Department of the Interior, Bureau of Land Management
Lake Ahtna—often spelled Atna—was a prehistoric proglacial (ice-frontage) lake which covered more than 3,500 square miles in the Copper River Basin, initially formed approximately 58,000 years ago during the Wisconsin glaciation, the most recent glacial period of the North American ice sheet complex. Other examples of prehistoric megafloods include Lake Agassiz and the Lake Missoula Floods, major catastrophic events resulting from the sudden drainage of proglacial or subglacial lakes, known by the Icelandic term jokulhlaups, and one such flood may have contributed to the destruction caused by the 1964 Alaska earthquake. Lake Ahtna existed in several forms, with several prominent shorelines observable in modern geology. The basin of the lake lay within an area bordered by the Alaska Range to the north, the Wrangell Mountains to the east, the Chugach Mountains to the south, and the Talkeetna
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