A day at the beach can change quickly when ocean conditions shift. Most swimmers are familiar with ordinary waves rolling toward shore, but occasionally the surface of the water can develop a strange checkerboard or crisscross pattern. These are commonly called “square waves,” although the more accurate term is a cross sea.
The pattern can look fascinating from the beach, almost as if someone has drawn a giant grid across the ocean. But it is not simply an unusual visual effect. A cross sea means wave systems are moving in different directions at the same time, creating a complicated and potentially hazardous sea state.
So if you’re ever at the beach and notice the water forming distinct intersecting lines or square-like patterns, the safest response is not to investigate from inside the water. Get out, move to a safe location, and follow instructions from lifeguards or local authorities.
What Exactly
There’s more to discover. Continue to the next page for the rest of this article.
