If the height of the wave is more than one-seventh the distance between the crests—the “wavelength”—the waves become too steep to support themselves and start to break. In shallow water, waves break because the underwater turbulence drags on the bottom and slows the waves down, shortening the wavelength and changing the ratio of height to length. In open ocean the opposite happens: wind builds the waves up so fast that the distance between crests can’t keep up, and they collapse under their own mass. Now, instead of propagating with near-zero energy loss, the breaking wave is suddenly
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