The Thame Flood: A Window into the Himalayan Climate Crisis

On August 16, 2024, a disaster struck Thame – the famous village home to many well-known mountaineers including Tenzing Norgay Sherpa and Kami Rita Sherpa. Two of the Thyanbo glacial lakes burst, unleashing a flood that destroyed 20 houses, an elementary school and a clinic. Fortunately, no lives were lost due to a combination of factors – primarily the timing of the flood. Since it was the off-season for tourists, the village was relatively empty. Additionally, the children at the elementary school had gone home early that Friday and the flood, known officially as a Glacial Lake Outburst Flood (GLOF), came during the day, at around 1:30 PM, giving inhabitants enough time to escape to safety.

However, while no lives were lost, around 135 people have been displaced as the settlement is now buried under debris. Unlike an earthquake, the disaster has left no land on which the residents can rebuild their homes. The flood has also left long-term implications. The Thame river, that used to flow through the left part of the Khumbu valley, has now changed course by flowing through the village and occupying almost half of the village’s land.

Unfortunately, this is not the first time that Thame has faced such a GLOF. Thirty-nine years ago, on August 4, 1985, an avalanche from the east face of the Tengi Rau mountain triggered a GLOF at Dig Tsho glacial lake. The outburst killed 12 people and destroyed many properties including the Namche Small Hydropower Plant which was set to be inaugurated in two weeks, resulting in an estimated loss of USD 1.5 million. Additionally, the flood washed away part of the Everest trekking trail leading to disruptions in tourism. However, yet again, despite the devastation, the timing of the disaster – during a Sherpa festival and the off-season for tourists – prevented even greater loss of life.

In both situations, luck and the timing of the flood played crucial roles in preventing the greater loss of life and property. If the recent GLOF had been any bigger or had come at night, it could have resulted in many more casualties and threatened five major hydropower projects on the Bhote Kosi, Dudh Kosi and Sun Kosi rivers, potentially leading to an energy crisis. However, given the increasing risks that GLOFs pose and the revenue Nepal receives from exporting electricity, leaving things up to chance is not feasible.

What is at Risk

GLOFs are not a new phenomenon. As defined by the International Centre for Integrated Mountain Development (ICIMOD), a GLOF is a “sudden release of water from a lake fed by glacier melt that has formed at the side, in front, within, beneath, or on the surface of a glacier.” Although these events have long posed a danger to mountainous regions, the probability of their occurrence has greatly increased. An ICIMOD report indicates that glaciers disappeared 65% faster in the 2010s than in the previous decade due to climate change. Additionally, global warming has meant that the moraines that create the dams of glacial lakes are rendered weaker than usual, further elevating the risk of GLOFs.

While the Thame disaster is the most recent evidence of the perils of climate change, the Sikkim flood that occurred in 2023 serves as one of the most striking illustrations of the dangers posed by GLOFs. On October 4, 2023, GLOFs in portions of the South Lhonak glacial lake caused a high velocity of water to flow downstream. The floods that occurred led to more than a hundred deaths as well as extensive damage to the Teesta hydroelectric dam – Sikkim’s biggest hydropower project. Similarly, in 2021, a glacial breach in Uttarakhand triggered flash floods that killed over 200 people and swept away two hydropower plants.

According to a 2020 research by ICIMOD, there are more than 25,000 glacial lakes in the region of the Hindu Kush Himalayas. Out of these, 47 are potentially dangerous glacial lakes (PDGLs) that lie within the Koshi, Gandaki, and Karnali river basins of Nepal, Tibet, and India, with 21 located in Nepal alone. Notably, the Thyanbo glacial lake that caused the Thame flood is not even listed among these PDGLs, yet is caused such significant destruction, thereby shedding light on the level of danger we face. Moreover, ICIMOD predicted that we will reach ‘peak GLOF risk’ by 2050 – merely 26 years from now. This puts a lot at risk – from lives to livelihoods to tourism, energy infrastructure and the broader economy. It also increases the possibility of climate-induced migration.

What has been Done so Far

Given the importance of glacial lakes and GLOFs, a significant amount of research has been conducted over the past few decades, particularly by organizations such as ICIMOD. Notably, there have been inventories of glacial lakes created as recently as 2020. However, data collection in Nepal has faced particular challenges as the country relies heavily on satellite images from international agencies and field visits are increasingly expensive.

Despite these obstacles, the extensive research available has led to some risk reduction efforts in the Hindu Kush Himalayas. In Nepal, this has been done for only two glacial lakes. The first is Tsho Rolpa – the largest moraine-dammed proglacial lake in Nepal. In May 1998, the country’s first flood warning system was installed here through a project costing approximately USD 1 million. In year 2000, an open canal was also constructed to lower the lake level by 3 meters, funded by a USD 3 million contribution by the Government of Netherlands. Similarly, in 2016, the water level of Imja Tsho, a glacial lake in the Everest region, was lowered by 3.4 meters through systematic draining. Some villages around the Imja glacial lake have also received trainings on how to respond in case of a flood. While these initiatives are notable, it is concerning that these are the only two glacial lakes in Nepal that have a risk mitigation plan.

On the other hand, the National Disaster Management Authority (NDMA) of India recently conducted various expeditionsand identified 189 high-risk glacial lakes in the Indian Himalayas. Additionally, they launched an INR 1.5 billion program to mitigate the risk of GLOFs by setting in place monitoring and early warning systems.

What Needs to be Done

Given the danger that GLOFs pose across the Himalayas, a variety of steps must be taken to mitigate their risks. First, systems must be put in place to monitor glacial lakes. Currently, Nepal largely depends on old satellite images from international agencies, unlike India, which has its own satellites through ISRO. Even the most recent inventory by ICIMOD relied on satellite images obtained from the European Space Agency’s Copernicus earth observation program in 2017. However, while satellite monitoring is crucial, it is also imperative to conduct in-situ observation, as demonstrated by the Thame disaster.

Second, based on the research that is obtained through these monitoring efforts, automated weather and water level monitoring stations (AWWS) and early warning systems (EWS) must be installed at glacial lakes and in downstream areas. However, implementing these measures is easier said than done due to the significant costs they incur. But it’s important to remember that these costs would be a mere fraction of the damage sum, should a major disaster occur. Therefore, proactive steps must be taken to secure funding to address these climate-induced threats.

In all of this, a crucial component that cannot be overlooked is the need for transboundary cooperation on these issues. Rivers and glacial floods do not respect borders. For example, many of Nepal’s rivers could be affected by glacial lakes in China. Therefore, the countries that host the Hindu Kush Himalayas must collaborate to conduct research and establish transboundary early warning systems to minimize the risk posed by climate change-induced disasters such as GLOFs.

Lastly, while all the steps mentioned above are preventative measures that countries can take to reduce the risk that GLOFs pose, none of this is enough if the world continues on its current path of exacerbating climate change. As the Thame flood has shown, the effects of climate change are not decades away, as is commonly perceived. Climate change is here. And it is affecting lives right now.

Therefore, Nepal must amplify its voice through climate diplomacy. We must share our stories and make the world aware of the perils we face. Despite being only 0.4% of the global population and being responsible for just 0.025% of greenhouse gas emissions, Nepal is the fourth-most climate-vulnerable country in the world. Why do we face such heightened risks when we are not the primary contributors to this crisis? While having a Nepal pavilion at COP 28 and hosting United Nations Secretary General Antonio Guterres to raise awareness are positive steps, much more remains to be done.

Time is ticking. When will we start to take charge?