On 7 February 2021, a glacier burst–triggered debris flow and flash flood occurred in the Rishi Ganga and Dhauliganga basins of Chamoli district, Uttarakhand. The sudden release of ice, rock, and snow generated an extremely high-velocity and high-volume debris flow that rapidly propagated downstream. The event washed away bridges and caused catastrophic damage to the Rishi Ganga and Vishnugad-Tapovan hydropower projects, including the destruction of tunnels and associated infrastructure. Downstream rural settlements and croplands suffered extensive losses due to sediment-laden floodwaters. The disaster resulted in the death of more than 200 people, including workers engaged in hydropower construction and operations. This event exposed the high vulnerability of Himalayan river basins to cryospheric hazards. It also highlighted the risks of large infrastructure development in fragile mountain environments. Strengthening hazard assessment, monitoring of glaciers, and disaster preparedness is crucial to mitigate future impacts.