**Glacier Collapse May Have Triggered Deadly Nepal Flash Flood, Experts Say**
A catastrophic flash flood near Nepal's border with Tibet on Wednesday has raised concerns among experts who suggest that the event may have been triggered by a glacier collapse. Satellite imagery from Planet Labs indicates that a significant portion of the lower part of a glacier broke off and fell onto the valley floor, which is situated hundreds of meters below.
Nepali officials have not definitively identified the cause of the glacier's collapse, but they have speculated that a recent earthquake in the region could be a contributing factor. The US Geological Survey later clarified that the tremor reported in the area was likely seismic energy generated by the collapse of glacial rock and ice, followed by a debris flow.
The aftermath of the disaster has been devastating, with nearly 170 bodies recovered so far. However, authorities on both sides of the border fear that the total number of casualties could be significantly higher, as approximately 1,500 individuals, including at least 700 foreigners, remain unaccounted for.
Before-and-after satellite images reviewed by Reuters depict a stark transformation in the landscape, with previously lush green mountainsides now buried under layers of brown debris and sediment. Vikram Gupta, an engineering geology expert from Sikkim University, confirmed that a substantial portion of the glacier snout collapsed, likely bringing down a considerable amount of rock and sediment along with it.
Dan Shugar, an earth scientist at the University of Calgary, noted that the satellite imagery suggests a rapid melting of snow in the 24 hours leading up to the disaster. He observed that many glaciers in the valley, which were covered in snow the day before, are now mostly bare ice, indicating a potential rise in temperatures. According to the United Nations, Nepal's snow-capped mountains have lost nearly one-third of their ice over the past three decades, with glaciers melting 65 percent faster in the last decade compared to the previous one.
Shugar further elaborated that the glacier collapse occurred at an elevation of approximately 5,200 meters, crashing down to the valley floor about 1,200 meters below. He also indicated that construction activities in the region could be a contributing factor to the disaster, and the role of climate change in this incident is likely to be scrutinized in the coming days.
Andrew Zolli, Planet's chief impact officer, announced that the organization plans to release more detailed imagery under an open license to assist in the emergency response efforts. Zolli echoed Shugar's analysis, suggesting that the glacier collapse may be linked to rapid melting, with the potential for climate factors to be examined further.
The affected area, particularly in the mountainous district of Rasuwa, is home to several hydropower projects and has a population of around 50,000. Nepal's National Disaster Risk Reduction and Management Authority reported that the flash flood, described as a "glacier-inclusive flood," occurred in the Lhende River due to a landslide approximately 20 kilometers northeast of a Nepal-China border crossing. Geologist Prakash Pokharel confirmed that the flash floods were caused by an ice-rock avalanche on the Nepali side.
The frequency and intensity of floods, landslides, avalanches, and droughts are increasing across the Hindu Kush Himalayas, posing a significant threat to local populations. The International Centre for Integrated Mountain Development has highlighted that the accelerating changes in water, land, and air in the region are raising concerns for the safety and livelihoods of those living in these vulnerable areas.
Reports indicate that the flash flood generated a powerful surge of water, sediment, and boulders through the Bhote Koshi and Trishuli river systems. In the Galchhi area downstream, water levels reportedly rose by as much as nine meters (30 feet) within just 30 minutes, illustrating the rapid and destructive nature of the flood.
As rescue operations continue, the full impact of this tragic event is still unfolding, with experts and authorities working to assess the situation and provide aid to those affected. The incident serves as a stark reminder of the potential dangers posed by climate change and geological instability in mountainous regions.