The answer is:

Waves usually run parallel to the shore, but a cross sea is different. It happens when opposing swells collide. The waves of the newer weather system run at an oblique angle to the old weather system, whose waves continue despite the wind shift, when the wind from two weather systems—one old and the other more recent—meet.

Although rare, the event is very harmful. From above, it appears as though an underwater grid is creating square-shaped ripples in these waves.

If you hike to the top of a cliff or lighthouse or fly a drone over the region, you can clearly identify the odd pattern.

Nevertheless, no situation occurring beneath the ocean produces square waves. Rather, they are the outcome of the water’s flow.

Cross-Seas Travel Is Very Risky

Even in situations with little swell, square waves can be very dangerous despite their striking appearance.

Get out of the water right away if you encounter square waves on the ocean. Why? because powerful, localized rip tides are typically linked to the event.

Even if you are a skilled swimmer or wave rider, you should avoid swimming or surfing in the middle of a cross-sea.

Shipwrecks and boating mishaps can also result from cross swells.

Although square waves are interesting, everyone is seriously threatened by these crisscross ripples, which are too powerful to escape.

Their maximum height is ten feet, or three meters.

On numerous beaches across the world, cross-seas can arise and dissipate in a matter of minutes, making them comparatively uncommon.