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Understanding Glacier Lake Hazards Through Satellite Monitoring
Recent studies have utilized satellite imagery to monitor the evolution of a glacier lake formed during a surge, providing insight into its life cycle and the associated risks for nearby populations.
Glacier surges involve a rapid movement of ice, leading to the advancement of its front, which can obstruct river paths and create lakes that threaten downstream communities and critical infrastructure with potential flooding.
The research, appearing in the Journal of Glaciology, focuses on a lake created by a surge of the Shisper Glacier, situated in the Karakoram mountain range that spans across Pakistan, China, and India.
Lifecycle of the Shisper Glacier Lake
The Shisper Glacier commenced its surge in early 2018, which led to the obstruction of a river and the formation of an ice-dammed lake. Researchers from the University of Portsmouth and the International Centre of Integrated Mountain Development studied this event using satellite images from the European Space Agency. Their analysis revealed that the lake experienced six distinct phases of both filling and drainage, a process that persisted even after the glacier’s surging phase concluded in 2020.
Notably, four of these phases resulted in the lake reaching its peak size by May each year, posing significant risks to the communities situated downstream. On average, the lake took approximately 155 days to fill completely.
In May 2022, the lake reached a notable volume of 33.7 million cubic meters—equivalent to over 13,000 Olympic-sized swimming pools. Each significant lake phase witnessed rapid drainage from May to July, typically occurring within one to two days, causing glacial lake outburst floods (GLOFs).
The GLOF event in May 2022 led to the collapse of the Hassanabad Bridge, an essential transportation link on the Karakoram Highway between Pakistan and China. This incident also wrought substantial damage to nearby homes, buildings, and hydropower facilities.
Community Protection Measures
Pakistan hosts the largest number of glaciers outside polar regions, underscoring the necessity for continuous monitoring of glacier surges and the lakes they form to mitigate potential damages in the future.
Dr. Harold Lovell, a senior lecturer and glaciologist at the University of Portsmouth, stated, “Predicting when glaciers will surge and whether they’ll create dangerous lakes is challenging, though certain settings indicate a higher likelihood. Satellite data enables the identification and tracking of surges, aiding in the forecast of future lake damming locations. This information is vital for alerting communities about periods of escalated flood risk.”
The research also indicated that hazards associated with glacier surges, like the creation of large lakes, can persist for years following the end of a surge.
Dr. Sher Muhammad, co-lead author from the International Centre of Integrated Mountain Development, noted, “Even after the Shisper Glacier ceased its surge and movement, the lake continued to form and drain for another two years, resulting in damaging floods that caused estimated losses exceeding $4 million in private property.”
“Nonetheless, our findings suggest that the phases of lake formation from the latest surge of the Shisper Glacier have concluded, potentially providing a period of relief for residents of Hassanabad village inhabiting its flood path.”
Regional strategies to diminish glacier-related hazards might include developing community-based early warning systems, constructing gabion walls for flood protection, and enhancing community and infrastructural resilience to withstand such natural threats.
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