What are square waves and are they dangerous? The cross-patterned marine phenomenon that could spell disaster for swimmers
- Everything you need to know about this strange aquatic phenomenon
You may have heard of a traditional rip current, but those enchanting square waves may have escaped your notice.
But, as gentle and intriguing as these waves seem, if you encounter them while enjoying the sea, it’s time for a quick exit to the safety of shore.
There are many types of waves – and these are not tsunamis – but it is important to avoid them as they can be catastrophic for surfers, swimmers and sea lovers.
So what exactly are square waves? Why are they dangerous? And why is it better to avoid them? Read on to learn more about the aquatic phenomenon.
The Ile de Ré in France (pictured) is a great example of how to enjoy square waves from the safety of earth
What are square waves?
These cubic squares in the sea are known as “cross seas”. They occur when different weather conditions moving in two separate directions collide.
In 2010, the European Space Agency stated that cross waves are actually quite common because they occur when “two swell systems” co-exist.
And scientists also say that this strange watery event is an example of the Kadomstev-Petviashvili equation in play.
These shifting winds mean that older waves continue and rather than crashing on the shore, they collide with newer waves.
The energy transfer created in the water creates a continuous disturbance that creates these ridges, which turn into squares.
So the squares are created, all because of two different sets of wind going against each other.
They can also be found both in the ocean and by the sea.
Why are they dangerous
This checkerboard pattern created on the watery surface looks beautiful to the human eye, but can be risky for surfers and swimmers who want to ride the waves.
But the real risk to swimmers, small boats, and surfers occurs when large cross waves occur, as cross waves can sometimes reach 10 feet high, or three meters.
Bigger waves from different directions can even cause boats to collect water.
It has also been shown that an excessive number of accidents occur due to these square waves, including a number of shipwrecks that have been caused by “cross seas” according to The sun.
If you get caught in a square wave because you didn’t recognize it in time, it can be quite dangerous.
The “swells” become much larger and you may find yourself desperately trying to escape two competing currents.
Likewise, waves around the globe are getting stronger due to climate change. This, combined with steadily rising sea levels, means the risk of damage to our seashores is becoming higher.

The energy transfer created in the water, by the wind, creates a continuous disturbance that creates these ridges, which turn into squares (pictured)

These checkerboard-shaped waves are usually seen in slightly shallower water. But can be very dangerous when swimming or on a boat as they can grow up to 10 feet tall
THE office met gave the following tips to help people avoid getting caught in these deceptive rip currents, which also apply to deceptive square waves:
- keep calm – don’t panic
- if you can stand, wade don’t swim
- keep your board or inflatable to help you float
- raise your hand and call for help
- never try to swim directly against the tear or you will get exhausted
- swim parallel to the beach until freed from the tear, then head towards shore
- If you see someone else in trouble, alert lifeguards or call 999 or 112 and ask for the coastguard.
Where are they common?
It is much safer and advisable to enjoy the gaze of this aquatic phenomenon in complete safety, with both feet and ten toes on the ground.
If you want to have a chance of spotting these square waves, it might be worth noting that they are usually seen in slightly shallower water.
The west coast of Ile de Ré in France has been spotted by this type of wave and is a great example of how you can safely enjoy this beautiful natural event.
These square waves were also seen in Tel Aviv, Israel.