Study of Decadal Retreat and Morphological Changes of Lirung Glacier

Glacier around the world is retreating at an alarming rate of 10m to 60m per year and Nepal Himalaya is no exception. This study is carried out in Lirung of debris covered glacier, located in Langtang valley near Kyangjin Gumba of Rasuwa district of Nepal. This study is carried out to measure length of retreat, rock types and vegetation in and around the ablation area. Metamorphic rock gneiss is the dominant rock along with small bushes and turfs without tree in the ablation area. There are total of 17 south-east and north-west facing ice cliffs covered by debris. The south-east facing ice cliffs were smaller in area than that of north-west facing ice cliffs whereas north-west facing ice cliffs were steeper that the south-east facing ice cliffs. The retreat rate of Lirung Glacier from 1980 to 1990 were observed to be the highest whereas retreat from 1990- 2000 were significantly lower. The length of retreat from 1980 to 1990 is 0.67km. Similarly the length of retreat from 1990 to 2000 is 0.27km, and the length of retreat from 2000 to 2014 is 0.45km The total length of retreat between 1980 and 2014 (34 years) is 1.40 km .The temperature rise is considered to be primary factor responsible for the glacier retreat. Hence, using high-resolution satellite images for small and medium-sized glaciers could be mapped and monitored regularly.