Have you ever heard of the "baïnes"? These phenomena of natural pools that cause numerous accidents every year on our west coast beaches and on the other side of the world, particularly in Australia.

So in this article we're going to look at how they work, what makes them so dangerous and how to protect yourself from them.

What is a bayonet?

Baïnes, a Gascon term meaning "little basin", are natural basins formed in places with special conditions, where the tidal phenomenon must be strong, the place relatively well captures the swell and the difference in level is small.

As you know, our fine sandy beaches change at the whim of the tides, winds and strong swells that affect our coastline. It's exactly the same for the baïnes, which are constantly in motion.

How are they formed?

When wave-forming swells break on our beaches, they gradually carry sand out to sea, forming sandbanks as the tides change. Their configurations sometimes bring us world-class waves.

When the tide goes out, the water between the beach and the sandbank will dig in and breach the latter. The tidal phenomenon will then increase the size of the sandbank and create a trough, the baïne. Each baïne is different in size, and some can be several metres deep, depending on the strength of the swell and the tidal range.

How they work 

Bayes may seem harmless to most bathers because they are so calm. However, it's underwater that the process begins!

During low tide, the basin is practically empty, so bathers, and children in particular, can come and bathe there without fear.

However, when the tide rises, the bay near the beach gradually fills up with the surplus water generated by the waves breaking on the sandbanks. The water level in the bay is therefore higher than the ocean level, and the surplus will drain out to sea, giving rise to "eddies" that cause strong currents pulling seawards.  

When the tide is completely high, the water levels between the bay and the sandbanks are equal, so currents are very low or non-existent.
When the tide starts to go out again, the phenomenon of currents starts up again until the tide is completely out.

The strength of this bay current will vary according to the depth of the breach formed there, but also according to the strength of the waves and tides.
For example, the current will be much higher at ebb tide than at flood tide.

Most of the time, the current that carries bathers out to sea is faster than their swimming speed, making it impossible to swim against the current to get back to shore.

How can you spot and protect yourself against baying?

At low tide, you can easily spot the small pools of water. At high tide, if you see areas of calm water with no waves, surrounded by waves that break and break in the form of foam, you're dealing with a bay.

If the beach you are visiting has supervised bathing areas, we strongly advise you to swim there and to respect the areas marked with flags. Don't hesitate to consult the information and bathing recommendations put out by the lifeguard post.

We advise against swimming outside supervised areas. However, if you are not sure where the safest swimming area is, don't hesitate to ask surfers and locals for advice.

What can you do if you're caught in a current?

First of all, if you're ever caught in a current, the first thing to do is not to panic and keep calm. As I said earlier, swimming against the current won't do you any good, and will only exhaust you.
The risk of drowning is only increased if you exert yourself in vain.

The best thing to do is to let the current carry you along without exhausting yourself, so that nearby lifeguards or surfers can spot you and come to your aid.

You can also try to swim parallel to the current in order to get out of it and then find yourself at the point where the waves break over the sandbanks. You can use the waves to help you get back to shore, or make it easier for the lifeguards to help you.

Whether you're a water sport enthusiast like longe-côte Whether you're a keen swimmer or an occasional beach-goer, it's important to be aware of the phenomenon of bay beaches when you visit them. If you don't already know how they work, it's essential to inform those around you about the risks involved.