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How waves break

As discussed in our previous article wind is the most important factor in creating waves. The speed, duration and fetch of the wind determine the height of the wave but there are many different other factors that determine the rideability of the waves. The shape of the bottom of the ocean plays also a huge role in how waves break. The bottom contour near the shore determines if the breaking wave will be good, big, small, hollow, slow or fast.

When predicting waves for your own surf spot these factors should be taken into account:

1 SLOPE OF SEA FLOOR

When a wave approaches the shore its bottom energy begins to drag across the ocean floor and slows down. The wave energy below the surface is pushed upwards causing the waves to increase in size. The wave breaks when the top of the wave overtakes the bottom. A swell unleashing its energy on a reef from deep water will create a larger and more hollow wave than the same sized swell moving up a gently sloping sandy beach.

2 SWELL DIRECTION

Each break has its own best swell direction. While some spots work well on a north swell, others are best with a west swell and offshore winds from the east. If you want to predict waves for your own spot make sure you know the its best angle for swell and wind.

Hossegor beach break on how waves break

Hossegor beach break    Photo by David

3 BEACH BREAK

Waves break on the sandy beach bed. The sandy bottom is a better choice for beginners. The conditions can change from day to day as the sand shifts around.

4 POINT BREAK

A point break is a wave that breaks on a section of land, usually rocks that juts out from shore. The swell wraps around these points creating perfect waves. Some of the best spots in the world are point breaks like Snapper Rocks in Australia or J-Bay in South Africa.

5 REEF BREAK

Reef breaks are waves that break on coral reef or rock seabed. They are consistent in wave shape and peak location. They are a joy to surf but if you wipe out in a bad spot they can be dangerous.

6 TIDES

Tides increase or decrease the sea level and is an important factor in the rideability of the waves. Some spots expose a reef when it is low tide making it unsurfable. Other spots work better with upcoming and high tide. When predicting waves for a surf spot it is an important factor to take into account.

Featured image by J.Bowen