Saint Simons Tides

Saint Simons Tides: What Makes St. Simons Island’s
Exceptional Tidal Levels?

Part of what makes St. Simons Island so unique is it’s exceptionally high tidal levels of rise and fall.? You’ll see six to 9 feet changes in sea level between low tides and high tides on a regular basis, which gives you really wide beaches for part of each day and much narrower strips of sand of course at high tides. Just part of the many things we here at Saint Simons Rentals love about St. Simons – so read on and learn some pretty incredible things, plus there’s some pretty cool images that’ll help make you look like an expert on the subject ;).

The Saint Simons Island exceptional tide differential is caused by the topological phenomenon known as the “South Atlantic Bight”, combined with the extraordinary width of the Continental Shelf at this point of the Eastern Seaboard.

Now to put that in layman’s language, what that means is that the really big rise and fall of the tides at Saint Simons is because it is in the exact middle of this big “U” shape on the East coast that? tends to concentrate all the tidal energy into the bottom of the U.? Plus the Atlantic Ocean doesn’t drop off to deep depths for a long, long way, so all this water gets shoved right up onto the shoreline in the high tides and then sucked quickly away again in the low tides.

Ok, now that you can see we won’t get too technical on you, let’s do a little bit more of the detailed explanations:

As we said before, St. Simons is right in the middle of the “South Atlantic Bight”.

In knot tying, a “bight” is a curved section or slack part between the two ends of a rope, and a “bight” is also a geographical term for a bend – in this case a rather large one in the coastline of the Eastern Seaboard of the United States.? Here’s what it looks like:
St. Simons South Atlantic Bight
This South Atlantic Bight is a really deep bend in the coastline – to put it in perspective, follow your finger North on a US map sometime and you’ll find that Saint Simons Island is just as far West as Pittsburgh Pennsylvania (but a lot more fun to visit)!

All this surrounding land mass has a protecting effect on the Georgia Islands, making the area much less susceptible (historically, so far) to hurricanes.? But the one thing that the South Atlantic Bight does do on a regular basis is that it concentrates the tidal flows.

note: Because the tides are so strong in this area it is really not recommended that you swim any distance out from the beach.? Enjoy the beach, get in the water and enjoy the waves, but keep in mind that the tides are very strong.

Also in the Geological Survey image you see the varying shades of light blue – this is the Continental Shelf.

The Continental Shelf is the area extending out from a shoreline that is relatively flat, just like a shelf.? The way you can think of it is this – it is like a swimming pool with a ledge built around it you can stand on while you are in the water.

As you can see in the image, the Continental Shelf off the coast of Georgia is very, very wide.? It looks like that huge bend that we call the South Atlantic Bight has really built up the sand over the centuries, so that the shelf extends quite some ways out from the coastline.

What this means in terms of your visitor experience at St. Simons is that the tides push huge volumes of water up onto this relatively shallow shelf every day, where it has no choice but to go up the beach and go inland.

Besides the beach getting wider and narrower daily, the really incredible thing is what these tides do the Georgia coastal waters, which has five rivers, nine estuaries, and because of the fourteen Georgia barrier islands and all the twisting river and estuary channels, there are literally thousands of miles of tidal shoreline along the coast of Georgia.

The tidal surges constantly renew the nutrients in these vast tidal estuaries, which are teeming with enormous varieties of wildlife.? The high and low tide surges mix with the fresh water flowing into the Atlantic from Georgia’s rivers, producing brackish water that is the optimal environment for many types of coastal plants and wildlife.

So as you can see, these tides produce a lot that you can experience in a relatively small area: estuaries, rivers, tidal coasts.? This is not just white sand beach, folks, this is nature’s bounty that is constantly changing.

A little bit more about St. Simons Continental Shelf:

Besides affecting the tides, the wide continental shelf also to a large extent determines what type of sea life you’ll encounter on the St. Simons shoreline.

Because the shelf is so wide, what you have are what is known as coastal fish, as opposed to deep ocean or pelagic fish.

What this means when you are on the beach is you are much less likely to see any sort of creatures that come anywhere close to “Jaws” size.? In fact, at the time of this writing, Georgia has never recorded a fatal shark attack: http://savannahnow.com/stories/071301/LOCbullshark.shtml

What this means when you are in the St. Simons beach water is that you aren’t in the water with the big boys.? Here’s a chart that will help explain this:

saint simons continental shelf

Continental shelf drop-off

Worldwide, you have a Continental Shelf around coastlines, some narrower than others.? As we already mentioned, the one off of Georgia’s coast is very wide.

Where the action is, and where you’ll see the “big boys”, is the continental drop-off, where the ocean floor suddenly drops to abysmal depth.? “Abysmal” depth is miles deep, so it is a radical change in the ocean at that point from the continental shelf depth.

This drop-off where the continental shelf ends creates a mingling of the oceanic waters between inshore and abysmal depths – there is a change in temperature, there is a change in the salinity, etc.? And there is a huge change in the oceanic life.? Like we said – that’s where to find the “big boys”, especially if you are fishing for them.

So I hope that makes you feel a little bit better about getting into the water at Saint Simons beach – that drop-off is miles and miles away!

So we’ve talked about the South Atlantic Bight and about the Continental Shelf, and how they are both exceptional occurrences at St. Simons.? We’ve talked about how they make the tides so strong, and how they constantly renew and make the Georgia coast so vital and so worth visiting.? We’ve talked about how all this affects your beach experience, even down to the types of creatures you might experience.

Now the next thing for you to do is to get yourself down to St. Simons Island and experience the Saint Simons tides for yourself.? We have a beautiful beach home with a location right off the best part of the beach at St. Simons – you will love it, just like we do, so call 404-822-4202 or email us at the Simons Rentals contact form so we can get you here and you can join in the fun!

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