Resources & Climate - Developing an Early Warning System for Debris Floods and

The earliest Himalayan earthquake in the historical record of Nepal dates to 1255 CE and reportedly claimed the lives of one-third of the population in the Kathmandu valley, including the king.30 In the year 1505 CE, a massive earthquake sometimes referred to as the Lo Mustang Earthquake, estimated to be between 8.4 Mw and 8.9 Mw, struck the Western Himalaya—killing perhaps one-third of the entire. [...] Such projections and plans existed before the Gorkha Earthquake—most substantively in formalized disaster plans that the Government of Nepal designed at multiple scales, the disaster management protocols of Nepalese security forces, and the projections of the National Society for Earthquake Technology-Nepal (NSET).45 In the wake of the Gorkha Earthquake, new rounds of disaster planning began almos. [...] 30 | Developing an Early Warning System for Debris Floods and Extreme Flow Events in Nepal The Langtang Avalanche that occurred during the Gorkha Earthquake is a terrifying and telling example of what an avalanche can be—it was the deadliest in the recorded history of the Himalayan region, and one of the deadliest in human history. [...] It created a pressure wave, referred to in the technical literature as an “airblast”, equivalent to a Category 5 hurricane that flattened houses and trees for more than a kilometer beyond the edge of the avalanche itself.84 The total volume of turbulent mass was estimated to be around 15 million cubic meters, about 15 times the size of the Empire State Building.85 When the front of the avalanche h. [...] For a variety of technical and economic reasons, the majority of these methods are not used in the Himalayan region - because of the scale of the terrain that would need to be monitored, as well as the prohibitive cost of doing so.