A devastating flash flood in Nepal’s Rasuwa district has killed nearly 100 people and left more than 400 missing, most of them tourists, after a sudden surge of water swept through the Himalayan region near the Nepal-Tibet border. More than 100 Indians are also among those reported missing.
An earthquake measuring 4.4 on the Richter scale struck the Himalayan region in the morning, triggering an avalanche that caused large chunks of ice to break off and fall into the river. With a large volume of water moving through a relatively narrow river channel, the waves reached heights of around 15 to 20 feet in parts of the Trishuli Basin. The water reportedly travelled at an estimated speed of 32 to 35 kilometres per hour. The number of glacial lakes in the state increased from 107 in 1990 to 669 in 2024, a rise of 525 per cent, according to the study. Their combined area increased from 5.5 square kilometres to more than 11 square kilometres, representing a 102 per cent increase. A separate report prepared jointly by the National Disaster Management Authority and the University of Zurich identified 56 of the 7,570 glacial lakes in India’s Himalayan regions as critical, meaning they are at risk of bursting. The world has 215,547 glaciers covering approximately 705,738 square kilometres, according to the Randolph Glacier Inventory. Central Asia has the highest number, with 54,429 glaciers, while South Asia, which includes India and Nepal, has 27,988. Alaska has 27,108 glaciers, Greenland has 19,306, while Western Canada and parts of the United States together account for 18,855 glaciers. A study published in Nature Communications found that glacial lakes exist across 31 countries and pose a direct threat to around 15 million people.
Because of shifting ice or rocks, earthquakes or cloudbursts, releasing large volumes of water downstream and causing sudden flooding, these dams can break.
China’s state-run news agency Xinhua, however, has claimed that the flooding in Nepal was caused by a mudslide in the Chinese territory and said some areas of China were also affected. The disaster began in the Himalayan region along the Nepal-Tibet border, where the Bhote Koshi River receives water from glaciers. This disrupted the flow of water, while continued inflow eventually caused the river’s banks to give way. The resulting floodwaters surged through the mountainous forests towards populated areas. Videos from the Nepal-China border crossing showed muddy floodwaters rushing through the area, sweeping people and vehicles away. In Rasuwa’s Trishuli Basin, the powerful current inundated buildings along the river and caused widespread destruction. There have also been allegations that construction activity in the Himalayan region contributed to the disaster. The flood has once again highlighted the growing threat posed by glacial lakes. When glaciers melt, natural dams made of soil and rocks can hold back the water and create lakes. Research by IIT Ropar and the University of Technology Sydney has highlighted the growing threat in Himachal Pradesh. The expansion of glacial lakes poses a threat to hydropower stations located along the Sutlej and Beas rivers. About half of those at risk live in India, Pakistan, Peru and China.
In today’s episode of DNA, Rahul Sinha, Managing Editor of Zee News, conducted a detailed analysis of the disaster, examining how the flash flood unfolded, the possible role of an earthquake and glacial water, the threat posed by glacial lakes across the Himalayas, and the response from Nepal, India and China.
Nepal has deployed its Air Force, with all 15 of its helicopters being used for rescue operations. The Indian Air Force has prepared C-17, C-130J and C-295 aircraft for assistance, while one aircraft carrying 10 tonnes of relief material has already departed for Nepal. All 36 gates of the Gandak Barrage in Valmikinagar have been opened, while NDRF and SDRF teams are being deployed in flood-prone districts. The affected region is reportedly around 30 to 40 kilometres from the Nepal-China border. If information about the glacier-related event had been received in time, people living downstream could potentially have had around 30 to 45 minutes to receive a warning and move to safety.
Because of the possibility of floodwaters entering downstream areas, india has also placed parts of Uttar Pradesh and Bihar on alert. In Bihar, the water level of the Gandak River has been rising due to water coming from Nepal. Because nepal had also expressed concern in 2024 after two major glacial lakes burst, this has drawn attention.
China did not provide Nepal with an early warning about the flood, according to the report. One bridge connecting the two banks of the Bhote Koshi River was also destroyed. After devastating Rasuwa, the floodwaters moved towards lower-lying areas, including Chitwan and Nuwakot. In Chitwan, large portions of a road were submerged, with only a statue of Lord Buddha visible above the water. Drone footage from Nuwakot showed large amounts of mud and debris accumulated around the Bhote Koshi River. The immediate danger has not completely passed. China has warned Nepal that water remains accumulated at the source of the Bhote Koshi River in the Himalayas, raising the possibility of another surge in the Bhote Koshi and Trishuli river basins. People living close to the two rivers have been advised to move away from the riverbanks. The disaster has also severely affected connectivity and rescue operations. Floodwaters destroyed bridges linking Rasuwa with other areas, making it difficult for rescue teams to reach affected locations. However, flooding has made helicopter landings difficult, slowing down the rescue effort. Amid the crisis, Nepal Prime Minister Balen Shah appealed to India for assistance. Prime Minister Narendra Modi spoke to Shah over the phone and assured Nepal of all possible humanitarian and relief assistance. Bihar Chief Minister Samrat Choudhary held a high-level review meeting on flood preparations. Alerts have been issued in East Champaran, West Champaran, Gopalganj, Saran, Muzaffarpur, Vaishali, Sitamarhi and Sheohar. Union Home Minister Amit Shah also spoke to Choudhary and assured him of assistance. In Uttar Pradesh, local administrations in Maharajganj and Kushinagar have been directed to remain alert, while Chief Minister Yogi Adityanath has ordered preparations for possible flooding. The disaster has also raised questions about the availability of early warnings. Nepal’s Department of Meteorology chief Jagadishwar Karmacharya had then alleged that China had not shared necessary information about glacier-related risks, potentially putting people in Nepal’s mountainous regions at risk.
Debris, including stones and wood carried down from the mountains, accumulated beneath the structure before the force of the water brought the iron bridge down in around two seconds.
Following the 2015 earthquake, India launched Operation Maitri to assist the country. The latest relief effort reflects India’s continued support for its neighbour as Nepal deals with the aftermath of the devastating floods.
India has historically responded to disasters in Nepal.
The first recorded flood occurred in 1935, and the river has experienced seven floods since then, with glacier water being a factor on each occasion. Nepal has experienced repeated flooding in the Bhote Koshi River. The latest flash flood has caused extensive destruction in Rasuwa and surrounding areas, with the full extent of the damage expected to become clearer after the floodwaters recede. As climate change accelerates glacier and glacial-lake changes across the Himalayas, the risk of sudden flood events is expected to remain a major concern for Nepal as well as downstream regions of India.
