How does the shape of San Luis Bay affect the dunes?
San Luis Bay is a log-spiral coast formed downcoast from resistant headlands (Point San Luis and the Pecho Coast [Diablo Canyon area]). As waves refract around the headlands, their orientation to the beach changes. Beaches off the dunes have long parallel wave fronts (waves have long crests and break all at once, as opposed to a good surfing wave with a progressive break). These parallel waves push sand onto the beach, whereas in areas where waves strike the coast obliquely, waves transport sand downcoast (littoral transport).
