Researchers studied swash bars on beaches in SW Spain to understand their shape and how they change over time. They looked at over 60 bars and found that bars on calm beaches are flat, while those on rocky shores are similar to bars on less calm beaches. Bars on calm beaches have layers of sand parallel to the shore, while bars on rougher beaches have layers that slope down towards the water. The shape of the bars and how they change are influenced by the waves, the shape of the bar itself, and the tides. Swash bars are more common in the spring and less common in the fall.