A natural ice dam in southern Argentina broke open spectacularly on Wednesday -- the first time it has burst in winter, prompting experts to say climate change was the reason. The 60-meter (200-foot) high wall of ice from the Perito Moreno glacier that usually divides Lake Argentina in Patagonia bursts from time to time under the built-up pressure of the held-back water.
The event is one of the prime tourist attractions of Argentina. But until now it had occurred in warmer seasons. This year's breaking of the dam was forecast well in advance, though the exact day was unknown, so relatively few visitors -- around 300 -- were on hand to photograph the phenomenon. Experts' predictions that the rupture could still be days away meant Argentine television stations were caught unprepared and were forced to air images of the last collapse.
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The glacier's ice dam does not break with any regularity, on average just once every four to six years.
It remained intact for 16 years until the last time it broke, on March 14, 2006, when 10,000 visitors and millions of television viewers watched the awesome show put on by nature.
http://www.terradaily.com/2007/080709172846.665tcdom.html