On February 7, 2021, a catastrophic landslide occurred in Chamoli, India on the southern hills of the Himalayas (N, E). About 28 × 10⁶ m³ of landslide mass detached from the mountain face, entrained deposits in the valley and riverbed, and generated a huge debris flood along the Dhauliganga River. In this study, the geomorphological and volumetric characteristics of the disaster chain were interpreted from satellite images. The full process of the disaster chain and the erosion, deposition and flow discharge processes were reproduced using a cell‐based analysis program, Erosion–Deposition Debris Flow Analysis (EDDA). The results indicate a peak flow discharge of the debris flood at Tapovan Hydropower Station of about 25,000–28,000 m³/s. The main erosion and deposition zones are distributed along the valley floor and the Dhauliganga River, respectively. This study serves as basis for understanding the disaster chain dynamics in high mountain areas.