Thursday, June 29, 2017
The massive Perito Moreno Glacier in Argentina
The glacier is unusual in that it is advancing, while most glaciers worldwide are retreating. The reason remains debated by glaciologists. The terminus of the Perito Moreno Glacier is 5 kilometres (3 mi) wide, with an average height of 74 m (240 ft) above the surface of the water of Argentino Lake, in Argentina. It has a total ice depth of 170 metres (558 ft).
Pressures from the weight of the ice slowly pushes the glacier over the southern arm ("Brazo Rico") of Argentino Lake, damming the section and separating it from the rest of the lake. With no outlet, the water level on the "Brazo Rico" side of the lake can rise by as much as 30 meters above the level of the main body of Argentino Lake. Intermittently, the pressure produced by the height of the dammed water breaks through the ice barrier causing a spectacular rupture, sending a massive outpouring of water from the Brazo Rico section to the main body of Lake Argentino. As the water exits Brazo Rico, the scored shoreline is exposed, showing evidence of the height of the water build-up. This dam–ice-bridge–rupture cycle recurs naturally between once a year to less than once a decade.