Waves are a product of the wind. When winds blow over the surface of the oceans, the energy is transferred to the water by the creation of swell, a group of traveling waves.
In 1939, Realist artist Edward Hopper painted "Ground Swell", in which sailors look a bit concerned about a possible wipe-out. Swells have been studied for centuries.
There are two relevant swells for surfing: ground swell and wind swell. Ground swells are the result of intense winds pressing the ocean water, thousands of miles away from the coast line.
Ground swells are usually the best sources of waves for surfing. When strong and intense storms and wind affect the waters, they produce "wave trains" that will make their way to the shores, where they will lose energy.
These long-distance winds produce the fetch. This is the area in which the winds apply their force and are often studied to understand the strength and direction of the future swell.
The fetch can produce large swell depending on the power of the winds. Fortunately, ground swells will lose energy during their journey to the shores. At the same time, the long-distance travel will improve the quality of the waves.
Ground swells create choppy wave conditions in the creation zone, but when the "wave train" reaches our surf spots, you get the cleanest surf with long wave periods.
What are wind swells? When local winds blow over the surface of the water, near the shores, they create wind swell waves. That is why short period waves will probably damage your local surf conditions, with choppy waters.
It is possible to discover the origin of the swell for the next days, in the Wave Height Forecast. Track long-distance swells heading to your surf spot, before hitting the water. Learn more about the formation of waves.