What triggered the devastating flash flood in Nepal?

28.08.26 - A raging flood wreaked havoc in a valley in Nepal near the border with China. We spoke with EPFL professor Christophe Ancey, an expert in natural disasters, about the underlying mechanisms and whether such an event could happen in Switzerland. Was it a mudslide, debris flow or a glacial lake outburst flood? On Wednesday, 26 August, a massive flash flood swept away hundreds of homes in a mountain region in Nepal, close to the border with Tibet. Initial assessments point to the collapse of part of a nearby glacier. But what exactly occurred from a geophysical standpoint, and could we see a similar natural disaster here in Switzerland? We spoke with Prof. Christophe Ancey , head of EPFL’s Environmental Hydraulics Laboratory and a specialist in fluid mechanics. A number of theories are currently making the rounds. At this point, what do we know for sure about the cause of the flood? First of all, it’s important to keep in mind that media outlets are throwing out a number of terms and theories – some of which are a little outlandish. So take those statements with a grain of salt. It’s still too early to know the exact cause of this catastrophe. Subglacial water pockets, debri