The speed of an ocean wave depends on the distance between two successive crests, its wavelength. The longer the wavelength, the faster the wave travels. A small surface wave, such as a ripple created by the wind, travels quite slowly because it has such a short wavelength. A swell, the larger, longer wavelength waves created by constant winds, have longer wavelengths and travel at higher velocities. The energy that the wave carries depends on the square of the height of the wave, which explains why high waves can cause so much damage to shorelines.