A flash flood began on 26 August in Nepal's Langtang National Park. The European Space Agency released Sentinel-2 and Landsat-9 imagery showing increased water volume and widespread inundation down the Lende Kholā and Trishuli valleys. The independent Nepali Times reports that a 1.5-kilometre cleavage in a hanging glacier on Langtang Lirung brought down up to 200 million cubic metres of debris. The avalanche triggered a 5.2 magnitude tremor and killed at least 389 people, with 1,400 missing.
Science··Midday
Satellites imaged the 26 August flash flood in Langtang National Park
The European Space Agency released before-and-after images of the flash flood that began on 26 August in Langtang National Park on the Nepal-China border. Copernicus Sentinel-2 and Landsat-9 imagery shows that river volume increased down the Lende Kholā and Trishuli valleys, and that the inundated area is wide. Optical satellite imagery is often the first way to map damage in high valleys that ground teams cannot reach. The agency says the flood was set off by a rapid slope failure.[1]
A hanging glacier collapsed on Langtang Lirung and fell 1,000 metres
The European Space Agency tied the slope failure to a glacier collapse on Langtang Lirung. The independent Nepali Times provides the mechanism: a clean cleavage about 1.5 kilometres wide occurred in a hanging glacier at 5,000 metres on the mountain's north face. The rock and ice tumbled down at least 1,000 metres onto the flatter glacier below. The avalanche brought down up to 200 million cubic metres of debris.[1], [2]
The collapse triggered a 5.2 magnitude tremor and killed at least 389 people
The energy released by the collapse was equivalent to a magnitude 5.2 earthquake. The European Space Agency reported this tremor magnitude, which Nepali Times confirms as a local 5.2 magnitude tremor triggered by the mass. The human cost is severe. Nepali Times reports that police have rescued 466 injured people, but at least 389 bodies have been recovered and 1,400 people remain missing in the debris.[1], [2]
