On our second day, we hiked up into the hills surrounding the lake to evaluate the threats to the lake’s stability: earthquakes, landslides, avalanches, and huge icefalls. Several members of the local communities met us. They needed information about the lake, our research and the potential for disastrous flooding. We discussed the threats to the downstream communities and the potential triggers of a huge flood, including the melting ice under the moraine and the possibility that lake water could seep through the hills surrounding the lake, which could cause the hills to collapse.
The Imja Glacier, melting and falling into the lake. (Photo by Daniel Byers)
Imja Lake was not formed until the early 1960’s. In those early days, the Imja Glacier ended at the moraine itself. As temperatures have risen, the Imja Glacier and the other glaciers that feed water to Imja Lake have been melting and receding, causing the lake to expand. In the future, if the glaciers continue to melt and recede, as expected, ice avalanches could fall into the lake, cause waves to burst over the moraine and flood downstream communities. Since these glacial lakes are a relatively new phenomenon in the Himalayas, too little is known about these risks. Even less is known about the potential solutions to lessen the risks. We are evaluating all these issues so that we can understand how much the lake will grow in the future, how the risk of floods may increase over time, and what can be done to diminish those risks.