Here's one way that sea cliffs get formed. Image by Why Files Staff. . A thin line of protection All geology is about change. Continents, as we know, drift gradually around the globe. The ocean floor is being created at the mid-ocean ridges and recycled beneath the crust at the margins.
Mountains rise up and gradually erode back.
These changes are slow, inexorable, and usually gradual. The changes on a beach, in contrast, can happen literally overnight, at least during a storm. Or sand may be pulled to deeper water, essentially lost to the coastal system. On the positive side, sand arrives from eroding uplands, river sediment, and longshore drift. That depends on recent storms.