Huge ice tunnel collapses into lake

RIO GALLEGOS, Argentina, July 10 (UPI) -- A 200-foot ice tunnel on a glacier in Argentina collapsed in a rare winter rupture some park wardens blamed on global warming.

The collapse on the Perito Moreno Glacier in the Los Glaciares National Park in the Patagonian province of Santa Cruz was "the first time the glacier has broken up in the wintertime," park warden Carlos Corvalan told London's The Telegraph newspaper.

The glacier, an important tourist attraction, collapses into Lake Argentino every two to 10 years due to water pressure from the Brazo Rico side of the lake. But the collapse usually occurs in the Southern Hemisphere summer, December through March.

Wardens speculated the winter collapse was due to global warming, The Telegraph said.

The glacier was first reported to have ruptured in 1917 -- a spectacular collapse that took with it an ancient forest of Chilean Myrtle trees. It last ruptured in 2006.

A few tourists and locals on a nearby observation platform witnessed the latest collapse of the ice tunnel roof.

The glacier is one of 48 glaciers fed by the Southern Patagonian Ice Field, located in the Andes system shared with Chile. The ice field is the world's third-largest reserve of fresh water.