Diverging Trends in Rain‐On‐Snow Over High Mountain Asia

Abstract Rain‐on‐snow (ROS) over snow‐dominated regions such as High Mountain Asia (HMA) modulates snowmelt and runoff is key contributor in influencing water availability hazards (e.g., floods landslides). We studied the trends ROS HMA past two decades from 2001 to 2018 using land surface model Noah‐MP driven by an ensemble precipitation data set. Our results show that changes phase rainfall are altering ROS. Because of strong physical heterogeneity atmospheric dynamics HMA, characteristics region‐dependent occurs predominantly Indus, Ganges‐Brahmaputra, northwestern basins. In representing ∼5% annual ∼20% snowmelt, has increasing trend. This contrary Ganges‐Brahmaputra characterized decreasing trends, where it represents ∼11% ∼60% snowmelt. basins, bidirectional due elevation patterns rainfall, constitutes ∼5 ∼10% precipitation. Increasing Indus contribute reducing snowpack late summer, with concerns reduced increased groundwater exploitation. Similarly, because its high amount contribution will have consequences decreased recharge headwaters exacerbated use unless compensate for These provide new insights on ROS‐driven hydrological cycle HMA.