A recent investigation into a glacier-induced lake in the Karakoram Mountains has showcased the utility of satellite imagery in tracking lake drainage risks.
This new research focuses on observing the changes in a glacier lake created by a surge, to enhance our understanding of its life cycle and the dangers it poses to neighboring areas.
During glacier surges, ice moves rapidly, with the leading edge advancing and sometimes blocking rivers. This leads to lake formation, increasing the risk of flooding for communities and infrastructure situated downstream.
The findings, published in the Journal of Glaciology, monitored a lake formed by the surge of the Shisper Glacier, which spans the borders of Pakistan, China, and India.
Lifecycle of the Shisper Glacier Lake
The Shisper Glacier began surging in early 2018, creating an ice-dammed lake by obstructing a river. Researchers from the University of Portsmouth and the International Centre of Integrated Mountain Development studied this using satellite imagery from the European Space Agency. They discovered that the lake went through six cycles of filling and draining, persisting even after the surge waned in 2020.
Four of these cycles resulted in the lake expanding significantly, reaching its peak size by May each year, thus posing threats to the safety of the communities below. On average, the lake took at least 155 days to fill up.
The largest phase of the lake accumulated a volume of 33.7 million cubic meters in May 2022—equivalent to over 13,000 Olympic-sized swimming pools. Each significant lake phase rapidly drained from May to July, resulting in glacial lake outburst floods (GLOFs) that typically occurred within one to two days.
The GLOF in May 2022 resulted in the collapse of the Hassanabad Bridge, a vital channel on the Karakoram Highway between Pakistan and China, and caused substantial damage to nearby homes, buildings, and hydropower facilities.
Safeguarding Nearby Communities
Pakistan contains the largest concentration of glaciers outside the polar regions. This study underscores the significance of vigilant surveillance of glacier surges and the lakes they create to mitigate potential future harm.
Dr. Harold Lovell, the lead author and a Senior Lecturer and glaciologist at the University of Portsmouth, remarked: “It can be challenging to predict when glaciers will surge and if they will form hazardous lakes, but we understand that this is more likely in certain conditions. Satellite data enables us to detect and monitor these surges, which may help identify areas where lakes could form in the future. This knowledge is vital for alerting communities about heightened flood risks.”
Moreover, the research indicated that dangers arising from glacier surges—such as the emergence of large lakes—can persist for years after the surge concludes.
Co-lead author Dr. Sher Muhammad from the International Centre of Integrated Mountain Development stated: “Even after the Shisper Glacier halted its surge and advancement, the lake continued forming and draining for an additional two years, resulting in damaging floods with losses estimated at over $4 million to private property.”
“Nonetheless, our data suggests that the cycles of lake formation due to the latest surge of the Shisper Glacier have come to a close, possibly providing a period of relief, particularly for residents of Hassanabad village who are affected.”
Implementing community-oriented early warning systems, constructing gabion walls for flood defense, and enhancing community and infrastructure resilience are potential measures that could lessen glacier-related hazard risks in the region.
