Wind waves

Most ocean waves are caused by the wind. A gentle breeze blowing over a short distance will create tiny little ripples. But even a moderate wind blowing over a long distance can create large waves. Once they start, waves will travel for hundreds or even thousands of miles.

Waves move as long, low ridges out at sea, with most of the wave below the surface (remember the post about tsunamis?) It’s not until they reach the shallows near shore that they are forced up by the ocean bottom.



As the wave is forced higher and higher, the water on the bottom is slowed down as it drags across the ground. The water on top is still traveling at the same speed, so eventually it topples over. This is what causes the breakers you see at a beach.

Surprisingly, very little water is actually carried in a wave. As long as the wave hasn’t reached the line of breakers, the water really just moves in a circle. These circles are large at the surface and get smaller and smaller as you get deeper.



In some places, if the waves are large enough, you can get a spectacular show. This is Blowing Rocks Preserve on Jupiter Island near the town of Jupiter on the east coast of Florida. On a calm day it’s just a pretty place. The only unusual thing is the presence of large limestone rocks. But when the wind blows hard enough to make large waves, they break on the rocks and send spray high into the air in a show you won’t see anywhere else. It's well worth a visit.