On the morning of August 16, 2024, the tranquil trekking village of Thame in Nepal’s Solokhumbu district was jolted by a disaster that, while not unprecedented for the region, carried a chilling new message about the future of the Himalayas. A catastrophic glacial lake outburst flood (GLOF) ripped through the valley, leaving a trail of destruction that, according to a new report by the International Centre for Integrated Mountain Development (ICIMOD), was the result of a complex chain reaction of natural events—one that is becoming alarmingly more common as the climate warms.
The study, titled Thame Valley Glacial Lake Outburst Flood – Causes, Impacts, and Future Risks and co-authored by Sudan Bikash Maharjan, Tenzing Chogyal Sherpa, and Arun Bhakta Shrestha, paints a vivid picture of the disaster. It began with a rock avalanche that crashed into a glacial lake perched at 4,900 meters above sea level. The impact generated a powerful displacement wave, breaching the lake and releasing 156,000 cubic meters of water. This torrent plunged 120 meters and slammed into a second lake, whose moraine dam then gave way, creating a yawning 22-meter-high and 51-meter-wide gap and unleashing an additional 303,000 cubic meters of water.
The combined waters didn’t just rush downhill—they became a “hyper-concentrated flow of slurry,” carrying with them huge boulders and debris for a staggering 80 kilometers downstream, eroding riverbanks and eventually covering the half-kilometer-wide valley floor near Thame. Homes, a school, a health post, a bridge, and even a hydropower plant were left battered or destroyed. Yet, perhaps miraculously, no lives were lost—a fact attributed to the phased nature of the flooding and its occurrence in daylight.
“The Hindu Kush Himalayas has more than 25,000 glacial lakes and Thame shows us that we need to spend much more effort in understanding and preventing the risks posed by even the relatively smaller lakes,” Sudan Bikash Maharjan, an ICIMOD remote sensing analyst and study co-author, told local media. “In this case, the additional geological and morphological characteristics of a landscape intensified the impact of this climate-driven event to cause catastrophic damages, though mercifully – with no loss of life.”
Thame’s ordeal is far from isolated. Nepal has experienced over 90 GLOFs since the early 1920s, and the Everest region alone has endured five significant events in less than 50 years. The infamous 1985 Dig Tsho GLOF, which devastated a newly built hydropower plant in a neighboring valley, still looms large in local memory. But the frequency and intensity of these disasters are increasing—and scientists say the culprit is clear: climate change.
The Hindu Kush Himalaya (HKH) region is warming at an average of 0.28 degrees Celsius per decade, according to the ICIMOD study. That’s nearly three times the global average, and the consequences are stark. Glacier mass loss in the HKH has surged by 65% in recent decades compared to earlier periods, fueling the formation of more than 25,000 glacial lakes across the region. These lakes, spanning the Amu Darya, Indus, Ganges, Brahmaputra, and Irrawaddy basins, are ticking time bombs—capable of releasing millions of cubic meters of water and debris in mere hours, obliterating communities and infrastructure downstream.
“As climate extremes intensify, the Thame flood is both a stark reminder and a moment of reflection, showing how mountain communities are already bearing the brunt of climate-induced disasters,” said Tenzing Chogyal Sherpa, ICIMOD cryosphere analyst and study co-author. “It reinforces the urgent need to invest in preparedness, strengthen scientific understanding, and support the people most at risk. Events like these also serve as crucial moments for understanding and communicating the realities of climate change, reminding us that the mountains are speaking, we just need to listen.”
The numbers are sobering. As reported by Policy Circle, Nepal has lost about one-third of its ice over the last 30 years. The situation is even more dire when looking ahead: ICIMOD estimates the HKH could lose up to 80% of its glacier volume by the end of this century, threatening water security for two billion people across Asia. Glaciers act as natural water reservoirs, and their retreat disrupts river flows that support drinking water, irrigation, and hydropower. The loss of this cryosphere could mean long-term water scarcity, which would ripple through agriculture, food security, and energy production.
Izabella Koziell, ICIMOD’s deputy director general, underscored the gravity of the situation: “The glaciers of the Hindu Kush Himalaya are a major component of the Earth system. With two billion people in Asia reliant on the water that glaciers and snow here hold, the consequences of losing this cryosphere are too vast to contemplate. We need leaders to act now to prevent catastrophe.”
But the impacts aren’t confined to Asia. Melting Himalayan glaciers are a significant contributor to rising global sea levels, with consequences that stretch far beyond the region. Rising seas bring increased storm surges, severe coastal erosion, and saltwater intrusion into freshwater sources, threatening communities around the world.
So, what can be done? The ICIMOD study, launched on October 13, 2025, at an event marking International Disaster Risk Reduction Day, calls for urgent and targeted action. Recommendations include protecting tension cracks in the landscape from direct water flow, reinforcing riverbanks to prevent subsidence, and developing a comprehensive flood risk management plan for the Thame valley. Perhaps most crucially, the study urges a dramatic increase in the monitoring of high-altitude glaciated regions, with more hydrological and meteorological stations providing real-time data and engineering interventions to protect vulnerable communities.
Arun Bhakta Shrestha, ICIMOD senior advisor and study co-author, put it bluntly: “The Thame case shows that glacial hazards are intensifying as the Hindu Kush Himalaya warms nearly three times faster than the global average. In the last two years alone, we have seen several high-altitude hazards including GLOFs, across the region. This points to two immediate needs: more hydrological and meteorological monitoring stations generating real-time information, and engineering measures including bank protection measures to reduce damages from future events.”
Beyond technical fixes, the broader solution lies in global climate action. “There is still time to save this critical region, but only if fast and deep emissions cuts start now. Every increment of a degree of warming matters to glaciers here and to the hundreds of millions of people that depend on them,” Koziell urged. Alongside urgent mitigation, adaptation funds, ecosystem restoration, and financial support for losses and damages must be rapidly scaled up.
Recent initiatives like the Building Adaptation and Resilience in the Hindu Kush Himalayas (BARHKH) project are already working to help governments prioritize climate-resilient investments and cut the cost and risk of future disasters. Still, as the mountains continue to lose their icy armor, the message is clear: the time for action is now, before more communities face the fate of Thame.