The Storm Above The Perito Moreno
It is summer and the valley echoes with thunder-like rumbles from the 'calving' of the ancient ice. Over 50km east, up in the Andes, it is snowing heavily, but it is drizzling where I am photographing. The Perito Moreno is my most fond glacier that I have had the opportunity to study and photograph. The trend of the glaciers of the world is to recede, but the Perito Moreno is actually growing. It is the only glacier out of 3 of Patagonian glaciers that is currently growing. There are a total of 48 glaciers fed by the Southern Patagonian Ice Field located in the Andes system shared with Chile.
"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 Lake Argentino, in Argentina. It has a total ice depth of 170 metres (558 ft)." - Taken from Wiki.
The most unique geological feature of the Perito Moreno is the 'rapture of the ice bridge'.
"Pressures from the weight of the ice slowly pushes the glacier over the southern arm ("Brazo Rico") of "Lago Argentino" ("Lake Argentina") 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 Lake Argentina. Periodically, 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 Argentina. 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.
"The last rupture occurred on January 19th 2013, and previously, March 4th 2012" - Taken from Wiki.
As you can deduce, the period between each rapture is drastically being reduced and is probably due to the subtle climate change.
Perito Moreno Glacier, Los Glaciares National Park.
- Jon K. Stoutlager