Abstract

Dynamic water storage reflects the movement of water within a watershed, including infiltration from the surface to the subsurface. In this study, we addressed two questions: (a) What are the spatiotemporal patterns of dynamic water storage during 13 extreme drought events? and (b) How do these patterns correlate with specific hydroclimatic and physiographic characteristics? To answer these questions, we analysed the variability of dynamic water storage dS(t), estimated via a water-balance approach as the increase or decrease in storage over time from the beginning to the end of the rainy season across 43 watersheds in south-central Chile (1980–2020), focusing on how meteorological droughts influence watershed storage dynamics. Our results show that dynamic water storage responds rapidly to precipitation, with maximum values ranging from 17 to 632 mm, and declines to negative values during dry periods. On average, storage peaks were observed 126 days after the onset of precipitation. The initial storage reduction during the droughts averaged 51 mm. Lower storage maxima are associated with drier climatic conditions (negative values of the standardised precipitation index [SPI] and the Palmer drought severity index [PDSI]), increased numbers of consecutive dry days in both summer and winter, and catchment characteristics such as higher elevation, steeper slopes and higher flow velocities. Seasonal shifts in storage, with accumulation at the beginning of the wet season and a rapid decline to negative values at the end of the dry season, reflect periods of water connectivity and disconnection, offering critical insights into hydrological modelling and drought mitigation strategies. We interpret the disconnection period as one in which surface water levels decrease owing to the absence of precipitation and increased evapotranspiration rates, highlighting the vulnerability of watersheds to extreme climatic events. © 2025 John Wiley & Sons Ltd.