Along the western coast of France, on the Île de Ré, is a great place to see them from a safe distance.

It can be hard for boats and swimmers to get through these cross-seas because they can make waves up to 10 feet high and change the way the wind blows.

Again, this is very unlikely to happen, but if it does, don’t go out on a boat or swim in the water, because it might be rough.

You could instead spend your time sitting on the sand or taking a quick dip in the shallow water until the weather is better. Then you can go into the water safely and without crowds.

What happens if you get caught in a square wave?

When you’re in the water, you might not notice that the waves are arranged in a grid, but you might notice that the swells get bigger and you have to swim against two different currents.

Not swimming out so far in the first place is best, and getting out of the water as soon as the waves get too big is also best.

More often than not, boats and ships farther out are in danger from square waves, so stay in the shallows to stay safe.