<p>This study investigates the spatial variability in dune erosion along Mexico Beach, Florida, during Hurricane Michael. Numerical simulations were conducted using the XBeach model and validated against post-hurricane field data, demonstrating good agreement in reproducing observed dune elevation changes. Results indicate that 89% of dunes experienced crest elevation losses exceeding half of their original height, with erosion predominantly associated with the collision regime, which accounted for over 70% of total crest elevation loss. For landward dunes, additional erosion occurred during the ebb phase, with sediments redeposited in nearby topographic lows. A linear relationship was identified between crest height loss and the Height-to-Width (H/W) ratio as well as collision regime, indicating that broader and taller dunes were more resistant to erosion. A critical crest elevation threshold of approximately 2.42 m, closely matching the modeled storm surge level, was identified as a dividing point between erosion and accretion responses. Alongshore variability in dune erosion was governed by geometric parameters and storm forcing conditions. Notably, crest erosion and toe retreat appeared to be decoupled, indicating the presence of distinct coexisting erosion mechanisms such as scarp collapse and basal undercutting, depending on site-specific dune geometry and location. These findings highlight the importance of considering longshore morphological variability in assessing coastal vulnerability and improving storm impact models.</p>