KATHMANDU, SEPTEMBER 2 Floods and mudflows along Nepal's Bhote Koshi–Trishuli river system have left an estimated 2.2 million tonnes of debris across the affected areas, according to a preliminary assessment by the United Nations Development Programme (UNDP). The assessment comes after the flash flood of August 26, reportedly triggered by a glacial collapse, swept water, mud and rocks through communities across the affected districts. Government figures cited by the UNDP show that 84,270 people across 17 municipalities in six districts have been affected. More than 1,000 people have been reported dead and over 4,000 missing, while 10,451 people have been rescued so far. The disaster has also caused major damage to Nepal's energy infrastructure. Eleven hydropower stations and one solar plant, with a combined capacity of 431.1 megawatts, have stopped operating. Another 15 hydropower projects under construction, with a planned capacity of 470MW, have also been damaged. Vulnerable communities hardest hit UNDP said the floods have disproportionately affected communities that were already vulnerable, with around three in four affected people living in areas facing greater difficulties in terms of livelihoods, 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. She said the scale of destruction was immense and stressed that recovery efforts should reach those worst affected and help communities rebuild safely and with greater resilience. Most of the affected municipalities are rural and located in Nepal's hill regions, where 67.4 per cent of people work in agriculture. UNDP said damage to crops, livestock and farmland could have long-term consequences for food security and household incomes. The timing of the disaster has compounded the problem, as Nepal's main monsoon planting season runs from June to September. More than half a million tonnes of building debris The preliminary assessment estimates that 556,200 tonnes of the debris came from buildings, based on satellite assessments covering damage to 2,359 structures. The figure is expected to increase as further damage is identified. The debris comprises parts of buildings, household belongings, vegetation, rocks and sediment. UNDP said the debris is also hampering search and rescue operations, with people believed to remain trapped or missing beneath collapsed structures and piles of mud and debris. The sheer volume of debris is expected to pose a major challenge as affected communities clear homes, roads and public spaces and begin rebuilding. UNDP prepared the assessment using satellite-based building damage data from Copernicus EMS and SERTIT, combined with other available data and locally adapted engineering estimates. The findings will be updated as more information becomes available. The agency said damage to hydropower and other energy infrastructure has further disrupted electricity supplies, complicating the restoration of essential services and the recovery process.