Factors controlling the accelerated expansion of Imja Lake, Mount Everest region, Nepal

• Main Authors: Thakuri, Sudeep, Salerno, Franco, Bolch, Tobias, Guyennon, Nicolas, Tartari, Gianni
• Format: Article in Journal/Newspaper
• Language: English
• Published: International Glaciological Society 2016
• Subjects: Institute of Geography; 910 Geography & travel; Annals of Glaciology
• Online Access: https://www.zora.uzh.ch/id/eprint/117201/; https://www.zora.uzh.ch/id/eprint/117201/1/ThakurAl16_AoG_ImjaLake.pdf; https://doi.org/10.5167/uzh-117201; https://doi.org/10.3189/2016AoG71A063

This study explores the link between area increase of Imja Tsho (Lake) and changes of Imja Glacier (area: ~25km²) under the influence of climate change using multitemporal satellite imagery and local climate data. Between 1962 and 2013, Imja Lake expanded from 0.03±0.01 to 1.35±0.05 km² at a rate of 0.026±0.001 km² a⁻¹. The mean glacier-wide flow velocity was 37±30ma⁻¹ during 1992–93 and 23±15ma⁻¹ during 2013–14, indicating a decreasing velocity. A mean elevation change of –1.29±0.71ma⁻¹ was observed over the lower part of the glacier in the period 2001–14, with a rate of –1.06±0.63ma⁻¹ in 2001–08 and –1.56±0.80ma⁻¹ in 2008–14. We conclude that the decrease in flow velocity is mainly associated with reduced accumulation due to a decrease in precipitation during the last decades. Furthermore, glacier ablation has increased due to increasing maximum temperatures during the post-monsoon months. Decreased glacier flow velocities and increased mass losses induce the formation and subsequent expansion of glacial lakes under favourable topographic conditions.