Perito Moreno Glacier

The glacier on the shore two weeks before the 2004 rupture

The Perito Moreno Glacier (50°29′S 73°03′W / 50.483°S 73.05°W / -50.483; -73.05Coordinates: 50°29′S 73°03′W / 50.483°S 73.05°W / -50.483; -73.05) is a glacier located in the Los Glaciares National Park in the south west of Santa Cruz province, Argentina. It is one of the most important tourist attractions in the Argentine Patagonia.

The 250 km² (97 sq mi) ice formation, and 30 km (19 mi) in length, is one of 48 glaciers fed by the Southern Patagonian Ice Field located in the Andes system shared with Chile. This icefield is the world's third largest reserve of fresh water.

Status

Large piece of ice collapses as the glacier advances

The Perito Moreno Glacier is one of only three Patagonian glaciers that are not retreating. 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).

Rupture

Two weeks prior to rupture.

Periodically the glacier advances over the L-shaped "Lago Argentino" ("Argentine Lake") forming a natural dam which separates the two halves of the lake when it reaches the opposite shore. With no escape route, the water-level on the Brazo Rico side of the lake can rise by up to 30 meters above the level of the main lake. The enormous pressure produced by the height of the dammed water finally breaks the ice barrier holding it back, in a spectacular rupture event. This dam/rupture cycle is not regular and it recurs naturally at any frequency between once a year to less than once a decade.

The glacier first ruptured in 1917, taking with it an ancient forest of arrayán (Luma apiculata) trees. The last rupture occurred in July 2008, and previously in 2006, 2004, 1988, 1984, 1980, 1977, 1975, 1972, 1970, 1966, 1963, 1960, 1956, 1953, 1952, 1947, 1940, 1934 and 1917. It ruptures, on average, about every four to five years.

The Perito Moreno glacier, located 78 kilometres (48 mi) from El Calafate, was named after the explorer Francisco Moreno, a pioneer who studied the region in the 19th century and played a major role in defending the territory of Argentina in the conflict surrounding the international border dispute with Chile.

Tourism

A "mini-trekking" group on the glacier.

Due to its size and accessibility, Perito Moreno is one of the major tourist drawcards to southern Patagonia. It is less than two hours by bus from El Calafate, and many tour companies run daily visits. A large visitor centre at the site features a walking circuit which allows both faces, and the surface of the glacier to be seen. There is also a restaurant at the site.

In recent years, trekking tours on the ice have gained popularity. The two standard tours are a "mini-trekking" option, consisting of a short walk of about an hour and a half, and a "big ice" version, which is usually about five hours. Tour companies generally provide crampons to customers.

Panoramic view from the visitor centre.

External links

Wikimedia Commons has media related to: Perito Moreno

• Glacier Perito Moreno LIVE '08 (Español, English, Français, Portugues)
• The Glaciers National Park
• ESA March/2004 Report
• Glaciology (Spanish)
• Associated Press on the March 2006 breach
• Santa Cruz Sub Secretary Of Tourism
• Panoramic virtual tour of Perito Moreno
• Video: Tourists watch as the 70 metres (230 ft) breaks down Sunday, March 15, 2004
• Photosynth (3D view) of glacier
• Argentine glacier advances despite global warming, June 14, 2009, The Associated Press