Abstract:As one of the most catastrophic geological disasters in the cryosphere, ice avalanche is characterized by complex movement process, high prediction difficulty, and severe consequences. On July 17 and September 21, 2016, two massive ice avalanche-debris flow events occurred in Ali Prefecture, Tibet, causing significant harm to the life and property safety of local residents and the ecological environment. PFC3D was used to invert the movement processes of the two events, and based on this, potential ice avalanche hazards in the surrounding areas were simulated and predicted. The results showed that: (1) The movement durations of the two ice avalanche-debris flows were 300 s and 240 s, with peak average particle velocities of 32.05 m/s and 34.80 m/s, respectively. The volume of the first ice avalanche that entered the lake was approximately 8.47×106 m3. (2) Energy transfer between the front and rear was the key mechanism for the high-speed and long-range movement of ice avalanche-debris flow. (3) It was predicted that the main accumulation area on the northwest side formed after the ice avalanche at Aru No. 85 Glacier (ice avalanche hazard) was approximately 1.1 km2, the small accumulation area on the northeast side was approximately 0.3 km2, and the total danger area was 3.28 km2. The result has scientific value and practical significance for ice avalanche disaster prevention and mitigation on the Qinghai-Tibet Plateau.