Groundswell

Groundswell is long-period swell energy that has traveled thousands of miles from a distant storm. By the time it reaches the coast, the individual wave trains have organized themselves into clean, well-spaced lines and sorted by frequency, creating the powerful, glassy surf most surfers dream about. Groundswells typically have periods of 13 seconds or more and can produce pumping waves days after the original storm has dissipated. Because groundswell energy penetrates so deeply underwater, it activates reefs, points, and offshore bathymetry that short-period wind swells never reach.