Knowledge of wave and surf conditions can play a major role in planning and executing a successful amphibious assault on a targeted beach (Figure 1). The dynamic surf zone is affected by waves that may have propagated from long distances (swell) and by refraction, which causes waves to become aligned with depth contours as they approach the coast. Local wind waves and tides can also change the character and width of the surf zone. Local bathymetry (e.g. beach profiles) can change dramatically due to wave action from storms. Offshore bars can form and migrate due to seasonal changes in wave dynamics and surf conditions. Accurate predictions of surf processes are dependent on models that contain the appropriate physics, and realistic environmental inputs to these models.