What Are Square Waves? And Are They Dangerous for surfers?

Last updated on: April 29, 2022
what are square waves? And are square waves dangerous for surfers?
The cross sea at the Île de RéPhoto by: Michel Griffon – Source: Wikipedia

Cross sea aka. square waves

Square waves in the ocean are actually quite rare. However, in France, one of the most common places to view them is Île de Ré – Isle of Ré. The island, located off the coast of La Rochelle, is one of the best locations to view square waves. These waves at the Isle of Ré resemble a grid when the two waves meet up and form squares in the ocean. Although beautiful to look at, square waves/cross-sea waves pose some risks to surfers and swimmers.

What Are Square Waves?

Sometimes called cross-waves, square waves occur when different waves from different weather systems meet at right angles.

It’s hard to visualize, but square waves could be compared to wedging waves in surfing terms. They occur when two waves from slightly different angles join each other and create a more significant wave or a larger peak.

What Causes Square Waves?

Square waves, or a cross-sea pattern, occur wherever waves from different weather systems meet at right angles. Most waves travel parallel and break horizontally, but square waves collide at right angles, forming the blocks you see.

How To Spot Square Waves

Square waves are easy to spot as the ocean starts resembling a grid pattern. There are wedges and hooks, and every wave gets broken up by the opposing wave. These squares are unique-looking waves, and you will spot them easily.

Cross sea - Square waves
Cross sea in Portugal – Source: Wikipedia

Why Are Square Waves Dangerous?

Square waves are dangerous for the simple reason that they come from two different directions and most likely two different weather systems. They are therefore accompanied by powerful and opposing currents. The result can lead to stronger combined currents as well as powerful rips.

Are They Safe To Surf?

There are some opposing thoughts on the safety of square waves. Mainstream media expounds on the fact that they are extremely dangerous, and you need to get out of the water immediately if you see them. The truth is that they’re not that dangerous if they are relatively small and might only pose a risk if they are big and powerful. Having said that, all waves that are big and powerful pose risks.
People surf small square waves all the time, and the feeling of surfing square waves is much like surfing a wedge. But to paddle out in these conditions, you have to be an experienced surfer and know the spot very well.

Where Are Square Waves Found?

These waves or cross-sea patterns can be found whenever two swells from different weather systems meet at different angles. They can also be seen when an artificial structure in the ocean influences swell direction by refraction. Finally, you can also find cross waves inside tiny bays when large cross-swells refract into these bays in more than one direction and form cross wave patterns inside the bay.

Square waves are responsible for shipwrecks at other maritime disasters. Still, these occur in the deep ocean with massive waves of incredible power forming square waves. The square waves that reach the shoreline have much-diminished power and are not as scary or as dangerous as everyone thinks.

Still, always be careful in the ocean and do not surf in waves if you feel you might be out of your depth.

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