But is there square waves? In reality, this is a phenomenon made up of a sequence of waves that intersect with different series oriented perpendicular to the first. It creates a kind of chessboard or grid formed by waves crossing each other at sea. Though rare, it is not unheard of. The terms inter-sea or square sea are commonly used to describe this occurrence.
The island of Ré in France, near La Rochelle, has become a popular vantage point for watching and photographing these peculiar waves. A current tower or observation point offers the best view of this striking natural event. Caution is advised against swimming in these waters due to the danger posed by the sea in such conditions.
These waves arise when two ocean currents collide at high speed. They can form deep in the ocean, but when they surface, they create risks for swimmers and boats alike. They may also occur when wind drags waves in one direction while the sea pushes them in another direction, according to meteorology sources that discuss coastal wave dynamics.
In Ré, boats have occasionally found themselves caught in these currents, though such events are not limited to that location. Worldwide, the square sea phenomenon can be observed in other regions under the right weather conditions, and it has become a notable topic for maritime observers.
Tel Aviv, Lisbon, and other coastal areas are known for producing square waves. While not a constant feature in any given location, the phenomenon appears when specific atmospheric and oceanic conditions align, offering a fleeting but powerful display of nature’s complexity.
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Environmental authorities provide guidance on how to stay safe in coastal waters, emphasizing awareness of changing sea states and avoiding coastal swimming when currents are unusually strong. The phenomenon is of interest to sailors, researchers, and travelers who want to understand how ocean interactions can yield dramatic surface patterns.