Glaciar Grande and Laguna Torre

by Martin Mergili

The Glaciar Grande (Large glacier) ends up in the Laguna Torre at the base of the Cerro Torre. The glacier tongue calving into the lake is best viewed from the Mirador Maestri, which can be reached in a 3-hour hike from El Chaltén. To arrive there, one first has to follow the trail to the Laguna Torre and, when having arrived at the lake outlet, to climb the moraine ridge on the right side of the lake all the way to the viewpoint. But be careful: the wind can be very, very strong, so that standing in an upright position might be a challenge!

The glacier and its surroundings: a dynamic system

26 February 2018

This image shows the lake with the calving tongue of Glaciar Grande, seen from the Mirador Maestri.

Click on the arrows or into the photo to learn how the glacier tongue and its surroundings have developed in the period 2006-2018.

Analyze the changes of the Glaciar Grande in the period 2006-2018 in the following way:

First, describe the general landforms you can see in the photograph.
Describe the changes between the individual points of time. Thereby, do not only concentrate to the glacier itself, but also to the surrounding slopes.
Interpret your observations with regard to the related geomorphological processes. If you are unsure, you can formulate two or more hypotheses.
Finally, try to predict the changes expected in the next 10-20 years.

Show solution

Description: the orographic left part of the glacier is debris-covered, whereas the right part of the glacier appears relatively clean. Parts of the glacier show high densities of crevasses. The glacier tongue retreats in terms of length, but also - and particularly - in terms of thickness during the observation period. Consequently, the surface area of the proglacial lake increases. Mainly in the period 2016-2018, the glacier terminus appears increasingly frayed, and the glacier surface uneven. Already in the 2016 photo, a small lake can be seen on the orographic left side of the glacier, which was not yet there in 2006. Obviously, this lake is connected to the Laguna Torre through a subglacial channel. In 2018, the ice bridge has disappeared and the formerly small lake is part of the Laguna Torre. On the orographic right slope, the vegetation has changed: close to the left edge of the photograph, the band of vegetations appears to have shifted downslope. In general, slope movements are apparent in various areas.

Interpretation: the debris-covered orographic left part of the glacier originates in a geomorphologically more active area and therefore receives more debris through landslides from the lateral slopes. The crevasses are the result of the movement of the glacier over an uneven basal surface. Glacier retreat is most likely a consquence of increasing air temperature due to climate change. In contrast to the Perito Moreno Glacier, this glacier appears not to receive its ice from the Southern Patagonian Ice Field, but from the slopes in its immediate vicinity. This might be the reason for its more rapid reaction to climate change. Mainly the debris-covered part seems to decompose internally (it is protected from direct solar irradiation). Debuttressing due to glacier retreat results in landslides on the adjacent slopes. This phenomenon is not only observed at Glaciar Grande, but also at many other glaciers worldwide - very clearly for example at the Fox Glacier in New Zealand.

Prediction: as the glacier tongue is thinning steadily, it can be expected that the glacier front will drastically retreat in the near future, most probably connected to the production of numerous icebergs: this trend is already observed in the photograph of 2018. Depending on the subglacial topography, the Laguna Torre may either grow, or it may be decoupled from the glacier. Furthermore, it has to be considered that a sudden acceleration of one of the slow landslides heading into the lake may lead to an impact wave which could not only put the people directly downstream at risk, but potentially also become a problem for El Chaltén.

Lliboutry, L. (1993): Thrust of Glaciar Torre over itself. Journal of Glaciology 39(133): 707-708 [Access source]

Lliboutry, L. (1998): Glaciers of Chile and Argentina. Geological Survey Professional Paper 1386 [Access source]

Masiokas, M.H., Luckman, B.H., Villalba, R., Delgado, S., Skvarca, P. & Ripalta, A. (2009): Little Ice Age fluctuations of small glaciers in the Monte Fitz Roy and Lago del Desierto areas, south Patagonian Andes, Argentina. Palaeogeography, Palaeoclimatology, Palaeoecology 281(3-4): 351-362 [Access source]

Winocur, D., Goyanes, G. & Viera, G. (2015): Movimiento de remoción en masa activo y su riesgo geológico asociado en la ciudad de El Chaltén, provincia de Santa Cruz. XIV Congreso Geológico Chileno [Access source]