Hurricane Francine struck Louisiana in September 2024, sending powerful waves from the deep Gulf of Mexico into the shallow, marsh‑filled Barataria Bay. Predicting how those waves change as they travel across open water, into narrow channels, and over fragile wetlands is hard because the physical processes act on very different spatial scales. We tackled this problem with a “zoom‑in” computer‑model approach. First, a Gulf‑wide model with 1‑kilometer grid cells simulated the storm winds, currents, and wave heights across the whole northern Gulf. The results from that coarse model then fed a second model with 100‑meter grid cells focused on coastal Louisiana. This high‑resolution model included detailed river flows and wetland channels, letting us see how waves lost energy once they hit shallow water and vegetation. We checked the model against instruments deployed during the storm, floating drifters offshore and water‑level/wave gauges inside the bay and found close agreement. The simulations show that wave heights dropped by more than half inside Barataria Bay because of depth‑limited breaking over sandbars, friction with the muddy bottom, and the maze‑like marsh shoreline. Mapping this wave‑energy loss helps scientists and planners estimate how future storms might affect other vulnerable deltas.