Are glacial lake hazards increasing in the Bhutan Himalaya?

"Project Description (4 years):
Himalayan glaciers have shrunk rapidly in recent decades, coincident with climate warming. Quantifying ice loss from these glaciers is vital, as they help to maintain water supplies to catchments with almost 1 billion people, outside of the monsoon season. To date, the Bhutan region of the Himalaya has been little studied, despite feeding the Brahmaputra River (~630 million people in the Ganges-Brahmaputra catchment) and housing a large number of glaciers. Many of these glaciers have large pro-glacial lakes, which both accelerate glacier loss and pose a major hazard when they burst. These glacial lake outburst floods (or GLOFs) cause major destruction and loss of lie and Bhutan (along with Nepal) has been identified as the country that is the most economically vulnerable to these events. Thus, it is vital to quantify how Bhutanese glaciers and their proglacial lakes are responding to climate change, to forecast changes in water resources and glacial lake hazards. However, previous hazard assessments in the region have used only remote sensing data, which misses key parameters (e.g. the height of the lake's moraine dam and its thermal structure) and has led to the same lakes receiving very different risk classifications. This project will address this issue, by using a combination of remote sensing, fieldwork and numerical modelling. Specifically, we will:
1. Use remotely sensed data to quantify proglacial lake expansion and changes in glacier dynamics (terminus position, ice velocities and surface thinning)
2. Collect field data at site(s) identified as a high risk for GLOFs in part 1, to conduct a detailed hazard assessment.
3. Integrate the field and remotely sensed data, of input into a model to determine downstream flood risk.
Overall, the project will improve our understanding of glacier change in a little-studied part of the Himalaya and will provide a framework for assessing GLOF risks for other proglacial lakes.
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