A massive rock and ice avalanche caused the 2021 disaster at Chamoli, Indian Himalaya.
Dan H ShugarMylène JacquemartDavid E SheanShashank BhushanK UpadhyayA SattarWolfgang SchwanghartS McBrideMaximillian Van Wyk de VriesM MergiliAdam EmmerC Deschamps-BergerM McDonnellR BhambriS AllenEtienne BerthierJonathan L CarrivickJohn J ClagueM DokukinS A DunningH FreySimon GascoinUmesh K HaritashyaChristian HuggelAndreas KääbJ S KargelJ L KavanaughPascal LacroixD PetleyS RupperMohd Farooq AzamSimon J CookA P DimriM ErikssonDaniel FarinottiJoel FiddesK R GnyawaliS HarrisonM JhaM KoppesA KumarS LeinssU MajeedS MalA MuhuriJ NoetzliF PaulIrfan RashidK SainJakob F SteinerF UgaldeC S WatsonMatthew WestobyPublished in: Science (New York, N.Y.) (2021)
On 7 February 2021, a catastrophic mass flow descended the Ronti Gad, Rishiganga, and Dhauliganga valleys in Chamoli, Uttarakhand, India, causing widespread devastation and severely damaging two hydropower projects. More than 200 people were killed or are missing. Our analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27 × 106 cubic meters of rock and glacier ice collapsed from the steep north face of Ronti Peak. The rock and ice avalanche rapidly transformed into an extraordinarily large and mobile debris flow that transported boulders greater than 20 meters in diameter and scoured the valley walls up to 220 meters above the valley floor. The intersection of the hazard cascade with downvalley infrastructure resulted in a disaster, which highlights key questions about adequate monitoring and sustainable development in the Himalaya as well as other remote, high-mountain environments.