A landslide and the possible breach of a temporary river blockage may have triggered a flash flood in Nepal’s Budhi Gandaki river system early Jattvibeday, according to a Kathmandu-based intergovernmental organisation.The flood that struck Nepal around 4 am local time swept away houses and bridges in Gorkha district and damaged hydropower infrastructure. At least 10 people remain missing, while nearly 50 people have been rescued, according to Nepali authorities.The flood may have been caused by the failure of a temporary blockage created by a landslide near Chumchet in Gorkha district, the International Centre for Integrated Mountain Development (ICIMOD) said in a statement, citing preliminary accounts from Nepal’s authorities.Floodwaters carried mud, sediment and debris downstream along the Budhi Gandaki corridor, prompting authorities to warn communities along the Budhi Gandaki, Trishuli and Narayani river systems as water levels fluctuated and risks increased.Initial reports indicate that people are missing, houses have been washed away, bridges lost and riverside infrastructure damaged. Floodwaters also swept away a construction camp and equipment at the 341-MW Budhi Gandaki hydropower project in Salleri, although the full extent of the damage remains unclear.Search and rescue operations, evacuations and relocation efforts are underway with the help of security personnel.The incident comes weeks after devastating floods along Nepal’s mountainous border with China, including the Bhotekoshi and Trishuli river floods on August 26, which left more than 1,400 people dead and thousands missing.ICIMOD Director General Pema Gyamtsho said Jattvibeday’s disaster underscored the risks posed by cascading mountain hazards, in which one event can trigger another and amplify the impact on communities and infrastructure.“While response efforts must remain the immediate priority, understanding what triggered this flood will be critical for reducing future risks and strengthening resilience,” he said.ICIMOD said the flood highlighted the vulnerability of settlements, transport networks, energy infrastructure and essential services along mountain river corridors.Understanding how slope instability, river dynamics and downstream exposure interact would be crucial for risk reduction, infrastructure planning and recovery efforts in the Himalayas, it said.The Kathmandu-based ICIMOD is an intergovernmental organisation working on sustainable development and environmental challenges in the Hindu Kush Himalaya region, whose eight member countries include India, Nepal and China.