WITH thousands of people flocking to the seaside to cool off, beach safety is all the more important.

And there is one phenomenon called “square waves” which are extremely dangerous for anyone in the water.

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Square waves are very dangerous if you’re in the ocean Credit: Alamy

Also called cross waves, they are similar to rip tides Credit: Alamy

Also called cross waves, the unusual wave pattern is formed when two different weather systems collide, creating the checkered effect.

This is because of the waves hitting each other as the they come rom different directions.

While they may look pretty, or even not very strong, they actually are much more dangerous than they appear.

They are similar to rip tides which can make it hard for people to get out of the water.

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They can be found both close to the shoreline and far out at sea – which has even resulted in causing shipwrecks, according to the European Space Agency.

Some of the places they have been spotted include La Rochelle in France, where they can seen from above via the lighthouse.

They are caused by two weather systems colliding Credit: Alamy

Places like Turkey (pictured), France and Portugal have all reported them

Last year, they were also spotted off the coast of Turkey, in the Aegean Sea.

Lisbon in Portugal and Hawaii are all places where they can occur too.

One person previously wrote on social media: “We were always taught to keep an eye out for the ‘squares’ – the grid can pull you back and fourth for hundreds of feet and make it hard to stay calm.”

If you want to avoid the ocean entirely, we’ve rounded up 10 of the best inland beaches in the UK.