The massive breach in the terminal moraine of Lhonak, and deposits of debris at the foot of the moraine, are testimony to the power that the flood must have possessed (Figure 15). In fact, most people probably walk by such features and ignore them for the beautiful snow and ice peaks jutting above, never realising that they are walking in the middle of a catastrophic event that changed people’s lives, livelihoods, and view of the world nearly 100 years ago. We certainly wouldn’t have known anything about the glacial lakes and moraines that we visited if we hadn’t consulted with local people along the way.
Back in the US, it was March of 2020 before I was finally able to start transcribing the recorded interviews and designing a framework for a scientific research paper. While rumours of a strange global virus were circulating, I contacted Mohan Bahadur Chand, a recently-minted PhD student at Hokkaido University and, coincidentally, one of Teiji Watanabe’s students.
Mohan’s 2020 PhD thesis was, in fact, about the development of glacial lakes in the Kanchenjunga region, and he was rapidly able to document the occurrence of five of the six GLOFs reported by local informants using before and after remote sensing images, mostly through the presence of flood scars, breached terminal moraines, and deposits.
He also located two additional smaller GLOFs that had not been mentioned, probably because they were smaller and located in remote regions near glaciers. Mohan had been aware of these events through his own research work, but he had been unable to assign approximate dates to their actual occurrence until provided with the results of the project’s oral history component.
Jonathan Lala, graduate student in engineering at the University of Wisconsin Madison, developed a numerical simulation model of the Nangama GLOF that strongly suggested that it was triggered by an ice/debris avalanche of some 800,000 m3of material, just like local people had thought, causing a surge wave that breached the terminal moraine and released an estimated 11 million cubic meters of water, with debris from the flood damming the Pabuk Khola river 2km below to form what is today known as Chheche Pokhari—just like local people had said.
Milan Shrestha, an anthropologist at Arizona State University, provided the methodological framework for oral history as a tool in recounting past GLOF events. He also provided essential information about mountain cultures and religious beliefs that helped immensely with our understanding and interpretations of many of the interviews conducted.
Plant ecologist Elizabeth Byers, when not photographing wild flowers for her new Himalayan wildflower app, was responsible for taking many of the field measurements of the Nangama glacial lake and terminal moraine that Jonathan Lala considered to be essential to his numeric modeling.
And Teiji Watanabe, whose article from over 20 years ago about the Nangama GLOF sparked the launch of our 2019 expedition, shared his vast expertise and more recent thoughts about the continued dangers of glacial lakes in the Kanchenjunga region.
Together, the different contributions resulted in our scientific paper published earlier this month in the journal Sustainability, ‘Reconstructing the history of glacial lake outburst floods in the Kanchenjunga Conservation Area, east Nepal: an interdisciplinary approach’.
In summary, the experience demonstrated the benefits and utility of using interdisciplinary research approaches to the better understanding of past and poorly documented GLOF events in Nepal and elsewhere, especially in remote, data-scarce high mountain environments rarely visited by scientists. Modern technologies and tools such as Geographical Information Systems, satellite imagery, and flood modeling are becoming increasingly sophisticated and valuable to our understanding of our changing world, but they have their own temporal and analytical limitations as well.
Involving local people in research can often help to fill these gaps in surprising ways. The research also demonstrates that while development agencies are busy writing up guidelines for mountain people to adapt to climate change and hazard risk impacts, these same people have been doing so for decades, if not for centuries.
They suffer (each flood mentioned killed many people and destroyed millions in infrastructure), they find ways to adapt (move to Ghunsa, graze the cattle higher), and they press on. Their resilience in the face of a history of unexpected GLOFs could provide some valuable lessons for us all, as we face the shock and completely unanticipated challenges imposed by COVID-19 and the global pandemic.
Listen to a podcast interview with Alton Byers in the Geopolitics and Ecology of Himalayan Waters here.
Alton C Byers, PhD is a Senior Research Associate and Faculty at the Institute for Arctic and Alpine Research (INSTAAR), University of Colorado at Boulder. A scientific version of this article, recently published in Sustainability, can be downloaded for free here.