The Bay of Somme records the most important tidal coefficients of the Channel.
There are two full seas and two low seas a day.
At low tide, the sea can retreat up to 12km towards the open sea.
At high tide, it goes the other way with a speed that can reach 2.55m / s.
In a few minutes the current brings everything in its path, encircling the sandbanks and covering them with several meters of water.
If this phenomenon is an unforgettable spectacle, it is no less dangerous.