Contrasting Patterns of Small and Large Glacial Lake Evolution in the Nepal Himalayas

The objective of this research is to assess annual ice velocities of three Himalayan glaciers in the Mount Everest region of Nepal. Glaciers worldwide are important indicators of climate change due to their tendencies of attaining equilibrium under changing climatic conditions. Imja, Lower Barun, and Hongu glaciers and their respective proglacial lakes have responded by retreat and growth, but at varying rates. Imja and Lower Barun Lakes have grown rapidly, but Hongu Glacier Lake has shown relatively slower growth. Despite the little accelerating growth of Hongu Glacier Lake, the moraine is composed of unconsolidated and unstable material, and poses the threat of an outburst flood due to less freeboard area. Therefore, it is important to monitor the development of all three lakes, as well as consider fluctuations of surface velocity. Using Landsat satellite imagery, I assessed the annual changes in surface ice velocity from 1992 to 2017. The yearly images were used as inputs to COSI-Corr, a co-registration and sub-pixel correlation software, to track changes on the glaciers surface. My results indicate short-term variations, despite all three glaciers’ location within the Mount Everest region, as well as similar long-term trends. Specifically, Imja, Lower Barun, and Hongu glaciers have shown long term trends of deceasing surface velocity, with varying rates of flow within each yearly pair. The three proglacial lakes have all grown at different rates as well, with Imja showing very rapid growth since the 1960s, Lower Barun showing deaccelerating growth, and Hongu showing very little growth. Understanding the dynamic nature of surface velocity can provide insight on overall glacier health, and may reveal how glaciers respond under rapid lake growth