November 6, 2014
Glaciar del Humo is in the Mendoza Province of Argentina. It drains into Lago Atuel and is one of the headwaters of Rio Atuel. Rio Atuel has hydropower development above and within the Rio Atuel Canon. The Nihuil dam and reservoir above the canyon and four more dams within the canyon, including Valle Grande Reservoir.
Le Quesne et al (2009) examined the retreat of glaciers in the Central Andes and reported the retreat of Glaciar del Humo as 3200 m from 1914-1948, 700 m from 1948-1970 and 660 m from 1970-2007. Here we utilize Landsat imagery to observed changes from 1990 to 2014.
In each image the red arrow marks the 1990 terminus, the yellow arrow the 2014 terminus and the purple arrow a glacier on the west side of Humo. In 1990 the Glaciar del Humo extended down valley ending at the red arrow at 3200 m. The side glacier ended less than 200 m from the main glacier. By 2000 the terminus had retreated 250 m. In 2003 there is little change from 2000. By 2013 the side glacier is separated by 350-400 m from the main glacier. The snowline is in the main accumulation of the glacier. In 2014 the glacier has retreated 900 m from the 1990 terminus position. The terminus is quite thin indicating that retreat will continue. There is also limited retained snowpack on the glacier in 2014, which would lead to mass losses and ongoing retreat. The retreat of this glacier follows that of others in the region, note Cortaderal Glacier. The loss of glacier area leads to a smaller ice cube to melt during the Austral summer, leading to less discharge for the hydropower project. This can be offset in the short run by increased ablation rate, but not beyond a 20% loss in glacier area.