Once one is a surfing vet, one of the most interesting aspects of it is searching for big, interesting waves that are fun to ride. Some of these are huge. For example, Mavericks off the coast of San Francisco, can reach up to 15 meters (50 feet). Another famous surfing wave, the Banzai Pipeline, breaks over a reef off the coast of Oahu, Hawaii. It’s one of many plunging waves that create a pipe-like space, or barrel, that surfers can fit inside.
Some of these waves are so big that swimmers can’t swim out to them safely, and need to be taken to them via tow-in skiing, or being towed behind a personal watercraft.
All waves, regardless of their size or shape are formed as a result of two basic factors. They are the interaction between wind and water and the interaction between water and land
Another influence is the tide. Lots of different factors affect tides, but the pull of the moon’s gravity is the biggest. There are also other factors that can contribute to tsunamis and other rare types of waves, but wind, water and land do most of the work when it comes to the waves used for surfing.
Ocean waves are what are called orbital progressive waves. The water molecules that make up the wave move in circles, or orbits, as the wave progresses. To help visualize this, picture the particles near the wave’s surface. If the wave is passing in front of you from left to right, the particles move in a circle in a clockwise direction. They move up the wave, across its crest and down into its trough.
The ocean’s orbital waves get their start when wind blows on the open ocean. A gentle wind doesn’t have much of an effect, as it just makes ripples in the water that spread the same way ripples do in a pond or a fish tank. But the stronger the wind gets, the more it pushes against the water. It transfers energy to the water as it makes peaks and white caps in the water’s surface. This region of white caps is chaotic, and the water can move choppily in all directions. The churning peaks give the wind more surface area to grab on to, which lets the wind force the water into even higher caps.
The height and shape of the white caps comes from three primary factors:
- How long the wind blew over the water
- How hard it blew
- The surface area of the ocean that the wind affected(called the “fetch”)
A very hard wind that has been blowing for a long time over a large area of ocean will result in large, frothy white caps, which eventually become large waves. This is why surf conditions are often good after a there has been a storm at sea. Satellite data used to track surface winds from outer space has aided forecasters in predicting when and where the surf will be high based on oceanic weather patterns.
