The Rongxar Qu, located on the southern flank of the Himalayas, is characterized by active tectonics and features abundant glacial lakes and moraines. Its stability was further compromised by the 2015 Nepal Gorkha Ms 8.1 earthquake. Following the clustered debris flows in the region on June 15, 2021, in-depth analysis has been limited, with little focus specifically on the activity patterns of the source materials. This study utilized pre- and post-disaster remote sensing data from GF-1B, BJ-2, and Planet satellites to interpret the debris sources of the debris flows. Additionally, the boundaries of typical glacial lakes were extracted using Landsat 5, Landsat 8, and Sentinel-2 remote sensing data through the calculation of the Normalized Difference Water Index (INDW). Furthermore, the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technique was applied to process 184 ascending Sentinel-1A data, enabling the acquistion of surface deformation in the region from 2014 to 2021 data. The results indicate that the study area experienced an overall trend of gradual subsidence from 2014 to 2021. In the landslide bodies, the most significant settlement occurred in the mid-upper sections, followed by the front edges, while the rear edges exhibited relatively minor deformation. This spatial differentiation pattern is attributed to the combined effects of frontal traction and middle-rear pushing forces, which caused the deformation to propagate toward the rear edges and resulted in overall slippage. Moraine-type rock glaciers demonstrated pronounced seasonal deformation, with the most intense deformation concentrated in their central zones, gradually decreasing toward the marginal zones and termini. This deformation pattern is primarily controlled by the freeze-thaw cycle of the active permafrost layer and the accumulation and release of meltwater in the central zones. Notably, Yalong Co Glacial Lake expanded by nearly 43% between 2000 and 2021, accompanied by significant deformation on both sides of the terminal moraine. Therefore, regional disaster prevention and mitigation efforts should focus on enhancing the monitoring of cryospheric hazards, including glacial lakes and rock glaciers, as well as the changes in debris sources connected to gully systems, particularly during the monsoon season.