The Perito Moreno Glacier is a glacier

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

 located in the Los Glaciares National Park

Los Glaciares National Park

Parque Nacional Los Glaciares is a national park in the Santa Cruz Province, in Argentine Patagonia. It comprises an area of 4459 km². In 1981 it was declared a World Heritage Site by UNESCO....

 in the south west of Santa Cruz province, Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

. It is one of the most important tourist attractions in the Argentine Patagonia

Patagonia

Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...

.

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

Southern Patagonian Ice Field

The Southern Patagonian Ice Field , located at the Southern Patagonic Andes between Argentina and Chile, is the second largest contiguous extrapolar extent of ice in the world...

 located in the Andes

Andes

The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...

 system shared with Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

. This icefield is the world's third largest reserve of fresh water

Fresh Water

Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...

.

Status

The Perito Moreno Glacier is one of only three Patagonian glaciers that is growing. The reason remains debated by glaciologists.
The terminus

Glacier terminus

A glacier terminus, or snout, is the end of a glacier at any given point in time. Although glaciers seem motionless to the observer, in reality glaciers are in endless motion and the glacier terminus is always either advancing or retreating...

 of the Perito Moreno Glacier is 5 kilometres (3 mi) wide, with an average height of 74 m (242.8 ft) above the surface of the water of Lake Argentino, in Argentina. It has a total ice depth of 170 metres (558 ft).

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

Luma apiculata, is a species of tree in the genus Luma in the family Myrtaceae, native to the central Andes mountains between Chile and Argentina between 33 and 45° South Latitude. Synonyms include Myrtus luma Mol., Eugenia apiculata DC., Myrceugenia apiculata Niedenzu, and Myrceugenella...

 (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

El Calafate

- Population :In the last census 6,143 permanent residents were counted . This represents a 20.1% increase compared with the 1991 census. However, due to the expansion of tourism, the population was estimated at 8,000 people in 2005.- Wildlife :...

, was named after the explorer Francisco Moreno

Francisco Moreno

Francisco Pascacio Moreno was a prominent explorer and academic in Argentina, where he is usually referred to as Perito 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

Due to its size and accessibility, Perito Moreno is one of the major tourist drawcards in southern Patagonia. It is less than two hours by bus from El Calafate

El Calafate

- Population :In the last census 6,143 permanent residents were counted . This represents a 20.1% increase compared with the 1991 census. However, due to the expansion of tourism, the population was estimated at 8,000 people in 2005.- Wildlife :...

, 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

Crampons

Crampons are traction devices used to improve mobility on snow and ice. There are three main attachment systems for footwear: step-in, hybrid, and strap bindings. The first two require boots with welts, the last adapt to any type....

to customers.

External links

• Glacier Perito Moreno LIVE '08 (Español, English, Français, Portugues)
• The Glaciers National Park