So that in case of their mobilization during an extreme hydrometeorological condition, a downstream threat perception can be assessed, and the vital infrastructures are protected. With this objective, the present study attempts to estimate the amount of paraglacial sediments stored in the two key tributary river valleys—Dhauli Ganga and Mandakini, in the upper Ganga catchment. Also, locations that can act as natural damming sites for force amplification in case of sediment mobilization during extreme weather events are demarcated. Using the published literature supported by remote sensing techniques, it has been observed that the Dhauli Ganga and Mandakini valleys have stored ~1467 × 106 m3 paraglacial sediment, making these valleys extremely vulnerable to extreme weather events. The study cautions that with global warming as a reality, where frequencies and magnitude of extreme weather events are predicted to increase, extreme caution is required while planning and executing the infrastructure developmental projects, particularly the hydropower projects in these valleys.