St. Helier Tides

 Jersey has a roughly 12 meter tidal range (the difference in "sea level" between the lowest and highest stages of tidal ebb and flood). It's hard to comprehend just what that means, but these pictures may help.

The difference in height between high and low water varies according to the monthly lunar cycle, with the largest difference occurring just after new and full moons (so-called "spring tides"), and the smallest difference occurring around the waxing and waning half-moons ("neap tides"). There are other factors that affect the tidal range, so there is also slight variation among spring tide ranges from month to month.

 We are, as I write this, at the height of this month's spring tide, with the port of St. Helier having an 11.2 meter difference between high and low water. Here in the marina, we are sheltered from the very lowest tide by a "sill", which traps water in the marina as the tide recedes, helping keep the boats behind the sill afloat. So the pictures below don't even reflect the entire tidal range.

This first pair of pictures was taken looking towards Idril, currently docked at the end of the "B" pontoon in St. Helier Marina. Note the large dark piling on the left (with a white cap labeled "B" on its top).

Low water

High water. Yes, Katy has her foot on the top of that same piling.

This next pair shows the "Welcome" sign on the marina seawall at low and high water.

If you look closely at the bottom of that railing, it becomes clear that even a slight storm surge would flood that sidewalk and street at the top of the seawall, to say nothing of what a meter of sea level rise would do.

There is a ramp from the pontoons up to the top of the seawall and the marina office and facilities. The angle of that ramp varies a lot, too. At high water springs, the ramp actually slopes slightly down from the pontoons to the gate.

Finally, remember that sill I mentioned, which we have to sail over to get into the marina? Here's the view from the outside of the marina at low water springs. The water in the marina is protected from going that low by the sill.

There are a few more pictures of the tidal range, including some "high water humor", in this album.