How to Read a Wave
For beginning surfers one of the most difficult things to do is judge when and where a wave will break. Experienced surfers do it almost intuitively and when asked may be vague or mysterious about how they’re doing it.
Basically, they’re using their knowledge of such things as wind direction, the profile of the seabed underneath, and the nature of the swells on that particular beach to make their decisions.
How Wind Affects Waves
If the wind is blowing offshore, it means the wind is blowing from the land to the sea. When there is a direct offshorewind, the waves will stand up a little higher before spilling over because the wind is literally shouldering into the wave, holding it up for a moment. This results in waves that break closer to the shore in shallower water and with greater intensity.
An onshore wind blows from the sea to the land and will push the waves over, making them break further out.
The contour of the sea bottom will also affect where waves break. In the ocean, moving water does not travel as one. Instead, the top layer of water moves faster than the bottom layer. As water approaches a beach and the sea bottom rises closer to the surface, the top layer slides up over the bottom layer, forming a swell.
How the Sea Bottom Affects Waves
A swell becomes a wave and breaks when the slower moving bottom can no longer support the faster moving top. Anomalies on the sea bottom such as sand bars can affect where a wave breaks by hindering the slower moving bottom, causing the top layer to overtop it earlier. If a succession of waves appears to be breaking in the same area, further out than the rest of the waves, this is a sign that a sand bar may have developed in that area. Experienced surfers may head to that area to take advantage of the consistency of the breaks there until the sea bottom shifts again.
In addition, surfers who surf a particular beach may know the profile of the sea bottom and use this information to position themselves. This is especially the case if there are reefs in the area. If they won’t share their knowledge, you can observe what they do and follow suit.
How to Return to Where the Waves Are
Finally, be aware that it is difficult for anyone to determine their precise position on the water when they are lying close to the surface. Even if you know more or less where you want to be, it can be difficult to be sure you are in the right place unless you align yourself with landmarks on the land. Once you find a good spot, pick out a tree or a point of land to align yourself with so you can return to that spot again.
By observing the direction of the wind and looking for anomalies that cause waves to break in clusters, you can locate a good spot where waves break more favorably. By aligning yourself with a landmark, you can return to that spot repeatedly. Experienced surfers do this intuitively, but you can do it to, by learning to read the waves.