As an ocean wave approaches shore, it reaches a point where the decreasing water depth causes it to slow and pile up. Wave frequency (number of waves in a period of time) remains more or less unchanged, but wavelength (distance between waves) is shortened, and amplitude (height between crest and trough) increases. Shortened wavelength and increased amplitude finally renders the wave unstable, and it breaks.
The seas on this day at Sunset Bay were quite calm, but the narrow opening to the bay at low tide meant that what waves were coming in off the ocean were well defined. Despite the curvature of the shore, you can see the waves are approaching it nearly perpendicularly across its length (despite the pesky botanical material in the way).