Everyone enjoys swimming during the summer, making beaches especially crowded. However, it’s important to stay alert near water as one mistake can lead to danger. While rip currents and changing tides are well-known hazards, one must also be aware of square waves.
Square waves, or cross seas, are among the most alluring yet dangerous phenomena in oceans or large bodies of water. These occur when two or more wave systems intersect, creating a checkerboard pattern on the water’s surface.
According to the European Space Agency (ESA) in 2010, “The conditions are quite common in the ocean and occur when a windsea and a swell, or two swell systems, coexist.” A 2004 study noted that “A large percentage of ship accidents occurred in crossing sea states.”
Cross seas can create swells up to ten feet high and unique wind patterns, making navigation challenging for both boats and swimmers.
If you encounter square waves, avoid boating or swimming in these dangerous waters. Instead, enjoy the beach and wait for conditions to improve.
Square waves, while beautiful, are hazardous. They often occur where two large bodies of water meet at a land tip, causing waves to intersect at different angles. The French Island of Ré, just off the coast of La Rochelle, is a prime location to observe these waves. Another notable spot is Cape Reinga in New Zealand, where the Pacific and Tasman Seas converge.
These stunning phenomena attract many tourists, particularly to lighthouses on the Isle of Ré. However, it’s crucial to observe square waves from a safe distance. While the sight of crossing waves is fascinating, not many have seen them firsthand.
In shallow waters, such as those off the Isle of Ré and Tel Aviv, Israel, observing two opposing surges is common. Scientists explain square waves using the Kadomtsev-Petviashvili equation, which describes nonlinear wave motion and the interaction between different weather systems.
