Tracking Hurricane‐Induced Water Storage Changes Using GRACE and GRACE‐FO Measurements

Abstract Landfalling hurricanes pose significant hydrological risks, yet monitoring their terrestrial water storage (TWS) dynamics remains challenging. Here we employed a new technique that estimates daily regional gravity changes from orbital perturbation measurements of the Gravity Recovery and Climate Experiment and its follow‐on mission to characterize TWS variations during Hurricanes Katrina (2005) and Laura (2020). Our spatiotemporal water storage maps reveal ∼40 Gt of accumulation by Katrina and a coastally localized ∼15 Gt by Laura, with coastal regions retaining up to 80% of precipitation but draining several days faster than inland areas. Despite differing magnitudes, both storms exhibited similar precipitation‐to‐TWS conversion patterns, implying consistent scaling of hydrological responses across intensities. Our observations also indicate that current land surface models, lacking surface inundation modeling, result in underestimations of flood recession rates. This work highlights satellite gravimetry's potential for continuous hurricane‐induced flood monitoring, offering a new tool to alleviate current observational difficulties.