June 24, 2013
Tour du Glacier is in the Valle de Chamonix and is one valley north of D’Argentiere Glacier and two north of Mer de Glace. Here we examine the retreat of Glacier du Tour from 1988 to 2011 using Landsat imagery and Google Earth. In each image the purple arrow indicates the 1988 terminus. The yellow arrow the top of an icefall at 2650 m. The orange arrow a prominent turn in the Little Ice Age lateral moraine. The red arrow a location along the 2011 ice front. Point A is an area on the south side of the glacier that is thinning, and shows little residual snow accumulation. Point B is another location near the top of a small glacier across the border in Switzerland where ice is being lost at the top of the glacier. Point C is where the tributary flowing from below Aiguille du Tour joins the Glacier du Tour.. In 1988 the glacier terminated at 2200 m, the icefall was 1 km above the terminus and the Aiguille du Tour tributary flowed into the Glacier du Tour. At Point B glacier ice still crosses the ridge at the top of the glacier. By 1999 the had retreated 100 meters, the Aiguille du Tour tributary still reaches the main glacier but is less than 200 m wide. By 2004 the terminus had retreated 200 m (red line) and the glacier is still quite crevassed near the terminus. In 2009 the area of the glacier around Point A has lost nearly all of its ice cover. Several rock knobs are protruding through the ice, purple arrows. The glacier has retreated another 200 m since 2004. At Point C the Aiguille du Tour tributary has a narrow finger that reaches the main glacier. In the 2011 Landsat image the Aiguille du Tour tributary no longer reaches the main glacier. At Point B the ridge that had been ice covered connecting two glaciers is now exposed. There is no snow left on the southern section of the glacier above and flowing down to Point a. The icefall region is now just 500 m above the terminus. The activity of the icefall indicates a continued active flow. The Aiguille du Tour tributary and portion of the glacier feeding Point A do not have significant retained snowcover and are not in equilibrium.
Landsat image 1988, purple arrow indicates the 1988 terminus.