The Uttarakhand region of India experienced a humanitarian tragedy on Feb. 7, 2021, when a wall of debris and water barreled down the Ronti Gad, Rishiganga and Dhauliganga river valleys. This debris flow destroyed two hydropower facilities and left more than 200 people dead or missing. A self-organized coalition of 53 scientists, including researchers from the University of Washington, came together in the days following the disaster to investigate the cause, scope and impacts.