Portillon Glacier, French Pyrenees- Retreating and Disappearing

Portillon Glacier is in the Luchon-Bagneres region of the French Pyrenees, just north of the border with Spain. This currently small, and becoming smaller glacier drains into Lac du Portillon, which has a dam impounding it for hydroelectric generation. Like the nearby Aneto Glacier, Portillon Glacier has been thinning, retreating and separating. First a comparison of photographs from 1900 and 2013. In 1900 the glacier fills most of the cirque and nearly reaches the shore of the lake. The lake level is lower at this time also. By 2013 the glacier occupies a few small niches near the head of the cirque.

portillon lac 1900
1900 image from the Lakes of the Pyrenees web forum

portillon 2013
2013 image from Julien Lacrampe

By 2006 Google Earth imagery indicates a glacier with an area of 0.12 square kilometers, red dots indicate the terminus of the glacier. Section 3 of the glacier has separated from the main section, 2. Section 1 is a narrow avalanche fed fringe beneath the cliffs. This section is too steep to retain good snow. In the 2008 image The glacier also is notably thin with few crevasses, and several bedrock outcrops amidst the thinning ice. Both the 2006 and 2008 image indicate the lack of snowcover on the glacier. This has exposed up to 75 annual layers in a closeup transect from head to terminus of the glacier. There are only a few crevasses on this relatively steep glacier, indicating the lack of movement, which can only come from thin ice on a steep slope.

The lack of persistent snowcover at the end of the melt season indicates a glacier,, like the Aneto and Maladeta Glacier, that will not survive current climate (Pelto, 2010). Its area is much less than Aneto Glacier, and it will disappear sooner. As SOER (2010) indicates more than 80% of the area of glaciers in the Pyrenees has been lost since the start of the 20th century. The color of Lac du Portillon and the loss of glacier in the basin reminds me of the Milk Lake Glacier, Washington that I watched disappear recently.
portillon glacier 2006
Google Earth image

portillong glacier best
2008 Digital Globe image

portillon annual layers

Saint Sorlin Glacier Retreat, France

The Saint Sorlin glacier above the resort of Saint-Sorlin d’Arves has lost over 50% of its surface area since 1870. The mass balance of the glacier is measured and reported annually to the World Glacier Monitoring Service, since 1980 the glacier’s cumulative mass balance is -28 meters water equivalent, equivalent to an average loss of over 30 meters in thickness The glacier is measured as part of the GLACIOCLIM program by the Laboratory of Glaciology and Geophysics of the Environment (LGGE) at the Université Grenoble. The LGGE has applied a glacier model that forecasts the disappearance of the glacier before 2100. The glacier retreat and accumulation zone thinning from 2002 to 2006 are evident in Google Earth Imagery. The average retreat during the four years is 60 meters, the red line in both images is the 2002 terminus position. More worrisome for the glacier is the expansion of bare rock areas high on the glacier, green lines outline the bare rock margins in 2006, which cross significant glacial ice just four years previous. . A view of the glacier from the hut beyond the terminus, from Lakiki, affords a view of both the thinning terminus (blue arrow) and rock outcrops emerging on the upper glacier (red arrows) that are a sign of a glacier that is thinning in its former accumulation zone. This is not a sign of a glacier that can survive (Pelto, 2010).