Kathmandu, 1 September 2026 – Floods and mudflows along Nepal’s Bhote Koshi–Trishuli river system have left at least 2.2 million tonnes of debris within the analysed areas, according to a preliminary estimate by the United Nations Development Programme (UNDP). 

See the full RAPIDA (Rapid Assessment and Analysis) for Nepal.

The flash flood, reportedly triggered by a glacial collapse on 26 August, swept water, mud and rocks through communities in the affected districts. Nepal has reported over 1,000 dead, with over 4,000 people reported missing.

A total of 10,451 people has been rescued to date. 11 hydropower stations and one solar plant, totalling 431.1 megawatts, had stopped operating. Another 15 power projects under construction, with a planned capacity of 470 megawatts, were also damaged.

The floods have hit communities already facing hardship

The floods have struck communities that were already among the most vulnerable in Nepal. Around three in four affected people were living in areas where people already faced greater difficulties with their livelihoods, access to basic services and living conditions.

“This is a devastating disaster for communities along the Trishuli corridor. Families have lost loved ones, homes and livelihoods, while entire communities are struggling to reconnect with essential services and one another,” said Kyoko Yokosuka, UNDP Resident Representative in Nepal.

“The scale of destruction is immense, and as the immediate response continues, we must make sure that recovery reaches the people who have been hit hardest and helps them rebuild safely and with greater resilience,” she said.

Government figures show that 84,270 people have been affected across 17 municipalities in six districts. Most of the affected municipalities are rural and in Nepal’s hill regions, where 67.4% of people work in agriculture. For households dependent on agriculture, damage to crops, livestock and farmland could have a lasting impact on food security and family incomes. Nepal’s main monsoon planting season runs from June through September, making the timing of the floods particularly difficult for farming communities.

For this assessment, UNDP has combined satellite-based building damage assessments from Copernicus EMS and SERTIT with other available data and locally adapted engineering estimates to map the scale and location of debris. The preliminary findings will be updated as additional information becomes available.

RAPIDA is UNDP’s Rapid Assessment and Analysis for Immediate Recovery and Development Action methodology, which provides governments and partners with timely evidence to inform early recovery planning following disasters.

The debris includes parts of buildings, household belongings, vegetation, rocks and sediment. An estimated 556,200 tonnes comes from building debris, based on satellite assessments of damage covering 2,359 buildings. This figure is expected to rise as more damage is identified.

For families and rescue teams, the debris is more than a measure of the destruction: people remain trapped or missing beneath collapsed buildings and piles of mud and debris, making rescue operations difficult and dangerous.

The amount of debris shows the scale of the destruction and the challenge communities face as they clear homes, roads and public spaces and begin to rebuild. Damage to hydropower and other energy infrastructure has also disrupted electricity supplies, adding to the difficulties faced by communities and slowing the restoration of essential services.

For more information, please contact: 
Monica Upadhyay, Head of Communication, UNDP Nepal, monica.upadhyay@undp.org, + 977-9841343953