Devastating flash floods and mudslides have wiped out buildings and bridges along the Nepal–Tibet border – with hundreds of tourists still missing.In Nepal, houses and roads were swept away by rushing water and mudslides.Meanwhile, officials in China–controlled Tibet said they feared 'major casualties'.So, why are these floods so catastrophic?According to Professor Liz Stephens, Professor in Climate Risks and Resilience at University of Reading, a 'complex chain of hazards' is likely to blame.'Most people think of flash floods as being caused by heavy rainfall,' she explained.'But in Nepal and Tibet, as in many other high–mountain regions, they can also result from complex chains of hazards, including landslides, avalanches and glacial lake outburst floods.'This complexity makes early warning especially difficult.' Devastating flash floods and mudslides have wiped out buildings and bridges along the Nepal–Tibet border – with hundreds of tourists still missing A boy looks at the devastation caused by flash flooding along the Trishuli River in Nepal's Nuwakot districtWhile details remain sparse at this point, early reports suggest a 4.4–magnitude earthquake triggered an ice avalanche, which in turn blocked the Lhende river.Water then built up behind the blockage before bursting downstream – with devastating consequences.Professor Stephens explained: 'Initial reports from Nepal suggest that an earthquake occurred around the same time as a landslide or avalanche, which then led to the catastrophic flooding.'One way this can happen in steep mountain valleys is when a landslide blocks a river, allowing water to build up behind it.'If that landslide dam, then fails, it can cause a sudden, devastating release of water and sediment downstream.'As it stands, it remains unclear if climate change had a part to play in these floods. However, a study published just last month in Frontiers in Climate warned the melting of glaciers and Glacial Lake Outburst Floods (GLOFs) will increase in the region as temperatures rise. 'Across the Himalayan region, warming rates exceed the global average, intensifying climate-related hazards and associated losses, contributing to the melting of glaciers and increasing the risk of GLOF, as some of the most visible indicators leading to climate change-induced loss and damage,' the researchers explained. While details remain sparce at this point, early reports suggest a 4.4–magnitude earthquake triggered an ice avalanche, which in turn blocked the Lhende river Water built up behind the blockage before bursting downstream – with devastating consequencesIs climate change to blame? As it stands, it remains unclear if climate change had a part to play in the devastaing floods. However, after floods in Nepal in 2024, scientists from World Weather Attribution said that climate change had worsened the floods. 'If the atmosphere wasn't overloaded with fossil fuel emissions, these floods would have been less intense, less destructive and less deadly,' said researcher Mariam Zachariah, from Imperial College London.Sadly, as temperatures continue to rise, scientists say that floods like this could become even more common. 'Climate change is no longer a distant threat,' said Roshan Jha, Researcher at the Indian Institute of Technology in Mumbai.'With every fraction of a degree of warming, the atmosphere can potentially hold more moisture, leading to much heavier downpours, and catastrophic floods like these.' 'Rising temperatures have accelerated glacier melt, altered snow cover dynamics and contributed to the rapid formation and expansion of glacial lakes, many of which are dammed by unstable moraine structures, and are prone to unexpected outbursts capable of generating destructive downstream flooding.'Meanwhile, after floods sparked by heavy rain in Nepal in 2024, scientists from World Weather Attribution said that climate change had worsened the floods. 'If the atmosphere wasn't overloaded with fossil fuel emissions, these floods would have been less intense, less destructive and less deadly,' said researcher Mariam Zachariah, from Imperial College London.Sadly, as temperatures continue to rise, scientists say that floods like this could become even more common in the region. 'Climate change is no longer a distant threat,' said Roshan Jha, Researcher at the Indian Institute of Technology in Mumbai.'With every fraction of a degree of warming, the atmosphere can potentially hold more moisture, leading to much heavier downpours, and catastrophic floods like these.'Authorities have so far found the bodies of 55 people following the natural disaster, amid fears that many more will be found as search and rescue operations get underway.Terrifying footage shows a tsunami wave of flood water crashing through a town, sweeping away everything in its path in the mountainous Rasuwa region of Nepal.In Tibet, one clip showed the Gyirong Port land crossing being annihilated by the flood. Dozens of people were seen running away in terror seconds before the water and mud crashed into the structure and wiped it out.There are fears that a second flood may send Nepal, Tibet and neighbouring India into further chaos. Flood alerts were issued in the populous northern Indian states of Uttar Pradesh and Bihar as they border Nepal and several rivers flow down the mountains into their plains.Nepali officials said hundreds of tourists and trekkers are unaccounted for, made up of 341 foreign nationals and at least 93 Nepali citizens.Among the unaccounted are 12 from the UK – including a 13–year–old girl – 105 Indian nationals, four from South Africa, 17 from Malaysia and three from the United States. One each from Australia and the Netherlands are also unaccounted for.