Snow Drought and Water Availability - A Multi-Source Data Assessment

Snow plays a crucial role in the Earth's systems, influencing land-atmosphere interactions and acting as a natural water reservoir. However, recent years have witnessed a decline in snowpack due to climate change and global temperature rise, raising concerns among the snow research and operation community. Consequently, there has been a surge in research dedicated to the investigation of snow drought phenomena. Emphasis has been placed on analyzing historical patterns and anticipating potential anomalies in the context of climate warming scenarios. Yet, the impact of snow drought on water availability, particularly in regions where snow contributes significantly to runoff, has not been thoroughly investigated. To address these gaps, we investigate the relationship between cold-season snow drought and warm-season water availability downstream, with a focus on hydrological drought at different temporal and spatial scales. To ensure a comprehensive approach, we integrate multiple sources of observations, including in-situ snow water equivalent (SWE), satellite remote sensing, and reanalysis datasets. The adoption of this ensemble approach offers a superior means of characterizing snow drought uncertainty, circumventing the limitations associated with sole reliance on a single data source, as observed in previous studies. We then compile an ensemble of datasets and develop an integrated snow drought index. Moreover, we explore the relationship between the developed drought indices and downstream streamflow changes, assessing the correlation between snow drought and hydrological drought. Our research contributes to advancing the understanding of snow drought phenomena and its implications for water availability. The findings will provide valuable information for water resource management strategies, especially in regions where snowpack significantly contributes to runoff and where potential changes in snowpack could impact water availability in the future.