Satellite view of Mont Saint-Michel Bay from Saint-Malo to GranvilleSatellite view of Mont Saint-Michel Bay from Saint-Malo to Granville
©Satellite view of Mont Saint-Michel Bay from Saint-Malo to Granville|Contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO
The spectacle of the high tides inThe Bay of Mont Saint-Michel

Why do Europe’s highest tides occur in the Bay of Mont Saint-Michel?

From Granville to Saint-Malo, the Bay of Mont Saint-Michel is the scene of a most impressive natural spectacle! You’ve undoubtedly heard that, at Destination Granville Terre et Mer, you can experience the highest tides in Europe. But why is it here and not elsewhere? Why is the tide weak in the Mediterranean? Why is it huge in the Bay of Mont Saint-Michel and in the Chausey archipelago? With these answers, you’ll be able to shine at your aperitif with friends. Be sure to reread the explanation of tidal phenomena in general before reading what follows.

The tides

a round story of bulges

When the moon and the sun act on the oceans, they create a sort of immense bulge that gives rise to the phenomenon of tides. In the Atlantic Ocean, which is very deep, there is an enormous volume of water. In the English Channel, on the other hand, there’s much less depth and therefore less water.

Imagine, then, that the Atlantic Ocean’s great bulge of water enters the English Channel in a matter of hours. The latter fills up much more significantly and its water level is much higher.

Waves connected to the frequency

Mont Saint-Michel

We must also take into account the relief of the Normandy coastline. In fact, when the famous bulges arrive along the Brittany and Normandy coasts, they can be deflected by the relief. For example, the nose of Jobourg in northern Cotentin will create detour that can be felt all the way to Mont Saint-Michel. The same applies to the Bay of Saint-Brieuc.

The Bay of Mont Saint-Michel, like a funnel receiving numerous marine currents, is therefore where these waves are most concentrated. As a result, the entire Bay of Mont Saint-Michel, from Cancale to Granville via the Chausey archipelago, is the place in Europe with the greatest tidal range, i.e. the greatest difference in water height between low and high tide.

To better understand all this, nothing beats the experience of crossing the Bay with a certified guide.