October 24, 2013

Yanashallasa Glacier Retreat, Peru

Posted by Mauri Pelto

Yanashallasa Glacier is near the southern end of the Cordillera Blanca in Peru. The glacier feeds the Rio Santa river, which provides irrigation for substantial agricultural acreage. Marks and Seltzer (2003) identify that at least 30% of the runoff comes from glaciers, rising considerably during the dry season. The glacier retreat in the region with a 22% area loss from 1970-2003 (Racoviteanu et al , 2008), will lead to continued decline in glacier runoff. Here we examine satellite imagery from 1992-2013 of changes in the Yanashallasa Glacier. yanas In each image the yellow dot marks the terminus, the pink arrow the same location on the west side of the glacier and the green arrow the same location on the east side of the glacier. In 1992 the terminus almost reaches a small lake beyond the glacier margin. The west margin indicates a wide connection of the glacier to slopes on the west side of the glacier. In 1999 and 2000 the glacier has retreated 150-200 m, the glacier still has a connection on the west side of the glacier. In the east side the glacier extends to the ridge east of the glacier even at the terminus. By 2013 the glacier has become disconnected from the slopes to the west of the glacier, pink arrow, the separation is a key sign of glaciers in disequilibrium. On the east side of the glacier the glacier has retreated from the east ridge at the terminus, green arrow. The losses in area along the lateral margins exceeds the retreat of the main margin, yellow dot. The main terminus retreated 250 m from 1992 to 2013. The impact of these glacier changes was assessed by USAID (2011). Other glaciers in the region are retreating in a losing mass Shallop Glacier Gurgiser et al (2013) and retreating: Quebrada Carhuascancha Glacier, Corihuasi Glacier and Chuecon Glacier in Cordillera Centrale adn Artesonraju Glacier similar fashion yanas 1992
1992 Landsat imagery

yanas 1999
1999 Landsat imargery

yanas 2000
2000 Landsat imagery

yanas 2013a
2013 Landsat imagery

yanas 2013
2013 Landsat imagery