June 18, 2011

Menlung Glacier Retreat, Tibet Glacier Moraine Dammed Lake Expansion

Posted by Mauri Pelto

Updated post is from April, 2015. Menlung Glacier is one valley north of the Tibetan border with Nepal and on the south side of Menlungste Peak. Menlung Glacier has a glacier lake at its terminus that is dammed by the glaciers moraine (27.95 N, 86.45 E). The glacier began to withdraw from the moraine and the lake form after the 1951 expedition to the area. The glacier lake is at 5050 meters, the glacier descends from 7000 meters with the snowline recently around 5500 meters. The Japanese Aerospace Exploration Agency has a side by side 1996 and 2007 satellite imagery that indicates the Menlung Glacier Lake developing in 1996 that still has remnant ice masses in it, that are gone by 2007. In Landsat imagery from 1992 the lake is still developing from a system of supraglacial lakes. Turning to better imagery available to the public in Google Earth in 2005 the lake has a contiguous area of with a length of 1100 meters and width of 700 meters (top). The lake rapidly expanded to a length of 1900 meters by 2009. The glacier retreat is 500 meters, the other 300 meters of expansion is a continued growth at the moraine end of the lake as ice cored moraine continues to melt (bottom). The lake is now substantial and still growing rapidly, with the rapidly melting terminus (black arrow). A look at the glacier surface indicates a large stream on the surface of the glacier that extends 2000 meters up glacier from the terminus (green arrow). This type of feature can only form on stagnant ice, otherwise movement generating crevasses would give a path for the stream to drain to the glacier bottom as is typical. The snowline in this 2009 image is at the blue arrow. . The retreat and lake expansion parallels that seen at Theri Kang and Imja Glacier.