Accurate characterization of peak snow water storage in High Mountain Asia (HMA) is essential for assessing the water supply to over one billion downstream residents. Currently, such characterization still relies on modeling due to the measurement scarcity. Here, eight global snow products were examined over HMA using a newly developed High Mountain Asia Snow Reanalysis (HMASR) dataset as a reference. The focus of intercomparison was on peak annual snow storage, the first-order determinant of warm-season water availability in snow-dominated basins. Across eight products the climatological peak storage over HMA was found to be 161 km³ ± 102 km³ with an average 33% underestimation relative to HMASR. The inter-product variability in cumulative snowfall (335 km³ ± 148 km³) explains the majority (>80%) of peak snow storage uncertainty, while significant snowfall loss to ablation during accumulation season (51% ± 9%) also reveals the critical role of ablation processes on peak snow storage.