Climate change directly linked to flood disasters in the Himalayas 

In the morning hours of October 3, the serene South Lhonak Lake transformed into an agent of destruction. What followed was a catastrophic flood disaster that would leave an indelible mark on India’s Sikkim region, claiming dozens of lives and reshaping the landscape of the Teesta River valley.In a recent study, experts have pieced together the dramatic sequence of events during this disaster. The research was led by Dr. Ashim Sattar of the Indian Institute of Technology in Bhubaneswar and Dr. Christian Huggel from the University of Zurich’s Environment and Climate research group.The findings paint a sobering picture of the escalating impact of climate change on mountain communities.On October 3, 2023, a sudden and catastrophic event triggered the flood. Approximately 14.7 million cubic meters of frozen moraine collapsed into South Lhonak Lake. This collapse caused a massive wave, similar to a tsunami, that reached up to 20 meters in height. The force of this wave breached the moraine, allowing nearly 50 million cubic meters of water to escape. This volume is equivalent to filling 20,000 Olympic-sized swimming pools, demonstrating the sheer scale of the disaster.As the water surged downstream, it carved through the 385-kilometer-long valley, causing unprecedented destruction. Sediment, estimated at around 270 million cubic meters, was displaced along the river’s course. Roads, bridges, and hydroelectric power plants on the Teesta River were washed away, cutting off communities and crippling local economies. The impact extended beyond infrastructure, affecting ecosystems and farmlands that depended on stable water sources.At least 55 people lost their lives in the disaster, while another 70 were reported missing. The suddenness of the event left little time for evacuation, increasing the human toll. Survivors faced immediate hardships as homes, livelihoods, and access to essential resources were swept away.“This event is a stark reminder of the vulnerability of high mountain regions to the effects of climate change,” said Dr. Huggel. “The thawing of permafrost and the instability of rock, ice, and moraine structures pose major risks.”To analyze the flood’s impact, the researchers relied on advanced scientific methods. High-resolution satellite images captured the affected regions before and after the event, allowing scientists to compare structural changes in the landscape. Digital elevation models helped reconstruct the terrain’s shifting contours, offering insights into how the floodwaters moved through the valley.Seismic data played a crucial role in pinpointing the exact moment of the moraine collapse. The tremors generated by the falling ice and debris provided a time marker for the sequence of events. Geomorphological studies further determined the volume of water and sediment released, helping scientists understand the flood’s full magnitude.By integrating satellite technology and physical modeling, the researchers creat