Historical snow droughts in the western United States (U.S.) and periods with a lack of snow accumulation or earlier snow melt have imposed substantial environmental and socioeconomic impacts. During drought, groundwater resources are often used to compensate for reduced surface water storage. This leads to depletion of groundwater resources in extreme conditions. As future warming exacerbates snow droughts, understanding the synergies between snow droughts and groundwater storage variations is crucial to sustainable water management in western U.S. In our study, we pose the following research question: How does groundwater storage respond to snow droughts in western U.S.? We used the Community Land Model (CLM v5), the land component of the Community Earth System Model, at a spatial scale of 12-km to simulate the land surface and subsurface processes of historical and future climates across the western U.S. The CLM applied here is calibrated against flow measurements for Catchment Attributes for Large-Sample Studies (CAMELS) watersheds. In our characterization of snow drought and its impact, we distinguish between two classes of snow droughts: 1) warm snow droughts (temperature-driven) and 2) dry snow droughts (precipitation-driven). We explore the spatiotemporal responses of groundwater storage to each type of snow drought. Our study aims to identify drivers of snow droughts and to understand the sensitivity of regional groundwater storage to future snow droughts under continued climate warming. The outcomes of this study will allow us to better predict water availability and guide the decision making for adaptive reservoir operations and drought monitoring to improve the resilience to extreme climates in the western U.S.