Maelstroms are ginormous whirlpools. They can exist continuously in an area. They're cool.

The question is, how large can they get? As large as an island? Could a maelstrom have a diameter of 60 or 100 km?

If so, could they be formed or maintained by natural causes and structures so that one could encircle an island constantly (as big as Jamaica for example)? As in, having an effective source beneath the island? (I know islands don't have sea under them, I'm talking about the effective center of the whirlpool)

What about a group of islands, where a massive maelstrom has a source between them? Could the tides encircle an island group (like the Seychelles in size)?

I'm asking if such a thing could exist with contrived (if necessary) but natural causes.

  • $\begingroup$ I stand a chance at answering this, because you asked it so you can't answer. :p (dang it, I forgot, you can answer your own question) $\endgroup$
    – DonyorM
    Commented Oct 10, 2014 at 12:58
  • $\begingroup$ @DonyorM xD You've got until I finish my lunch! j/k I ask this because I don't have any idea on how to answer it tbh. $\endgroup$
    – mechalynx
    Commented Oct 10, 2014 at 12:59
  • $\begingroup$ I can answer :D $\endgroup$
    – Tim B
    Commented Oct 10, 2014 at 13:01
  • 1
    $\begingroup$ j/k - I'd need to do some research and no time at the moment. $\endgroup$
    – Tim B
    Commented Oct 10, 2014 at 13:01
  • $\begingroup$ This is tough. You could probably pull it off pretty easily in some extra-galactic planet covered in a superfluid like liquid helium. $\endgroup$
    – Black
    Commented Oct 10, 2014 at 16:18

3 Answers 3


Using a little power-scaling math because simulation at this scale is difficult, and the rules break down at large scales anyway:

No, No island. At least not for Earth-typical conditions and continuous existence.

First, a free vortex is needed. But it needs to be physical and have room for Jamaica in the center, so we'll choose a Lamb-Oseen vortex which can get a stable center. Based on that you need a viscosity much much higher than water to get a center region larger than 1 meter. For water you'll have an edge velocity close to Γ/188.5 km. Γ is an integral that is larger at larger radial distances.

Assuming you could ignore the slowing effect of a central landmass, you still need additional extra input to keep the whole thing spinning against the losses from viscosity. Near the equator you can pull about another 1 meter/sec from the Coriolis effect at 50 km radius and Earth's Coriolis Parameter. As far as tidal forces and pressure forces, at Saltstraumen you have the strongest tidal forces on earth at 41 km/h yet they only create 10 meter whirlpools. If we increase that number by 300 km/h for some of the strongest thermal currents on Earth, the Katabatic wind). And then if we scale linearly, we could possible walk away with 83 meter diameter whirlpools.

If instead of instead of a singular whirlpool you can accept a chain of smaller ones then I don't think there is an effective limit as you just need more turbulence. The vorticity at high energies in a turbulence will create little whirlpools everywhere.

Yes, If you toss the island requirement then your 100 km region is very doable. The Great Red Spot can have several Earths fit inside it for example.

I can also see turbine-shaped mountain ranges from pole to pole that gradually smooth out. A rapidly spinning planet would have the water forced towards the poles from the mountains and the centrifugual force would tend to force the water towards the center. Circulation would form a whirlpool I would imagine. The setup balancing Roche limit, pressure, and centrifugal forces would be tricky to compute because calculating pressure would be hard.

  • $\begingroup$ This is great! I don't have upvotes left for today but I'll certainly +1 this asap. $\endgroup$
    – mechalynx
    Commented Oct 11, 2014 at 16:35

Saltstraumen and Moskstraumen can both be up to 8km wide. I know of no reason why they could not be bigger. The terrain needs to be correct, such that water is trying to move very fast through an opening which is relatively small. In the case of some whirlpools, the constraining passage can be underwater.

I do not believe that a landmass could be engulfed in a maelstrom though. The existence of an island inside of it would make the vortex more difficult to form. Try it at home... If you take a pan full of water and start swirling around the edges, a little whirlpool will form. Now try it with a bundt pan. Moving the water around is much more difficult, and the water will slow down faster.

FYI - Whirlpools can be caused by non-natural events as well. Lake Peigneur in Louisiana was the site of a maelstrom resulting from aberrant drilling. I'm surprised no Bond villain has tried this...


This almost deserves to be a comment, but too long for that format. I have no clue on the feasibility of this.

Lets take an impact crater lake...impact craters tend to leave glass bottoms which won't let water through. Put a hole at the bottom of said impact crater that drains into underwater passages and eventually out to an ocean. This should create a decent sized whirlpool. Gives it a nice uniform round/cone shape as well.

Lets scale this up and feed a couple rivers into the system...if the rivers enter the crater at the right angle, the flow of the river will help power the rotation of the whirlpool.

Now lets take another mass of land and drop it into the vortex so it sits touching the edges of the crater without actually blocking the drainage hole at the bottom (sadly, this would kinda look like a raised stopper in a bathtub). This mass of land would have to be one solid chunk and large enough that the top of it is your island. Would be best if it was resistant to erosion as well if you wanted a decent lifespan on this setup.

Possible that this setup leaves you with a crater lake and a spinning whirlpool around it. I'm really not sure if this setup is feasible from a 'how did that land get there' standpoint, nor can I really prove this setup would perpetuate a whirlpool. This wouldn't really be a series of islands in the ocean (unfortunately the ocean setup always leaves the question of 'where does the water drain to then?')...just a crater lake with a whirling mass of water spinning around it.

**how about the Flash is running around in circles at the bottom of the ocean around the Seychelles?

  • $\begingroup$ I like this idea. I don't know how it would form, but geothermal heating could drive this setup. Maybe a magma chamber under the sea receding and then collapsing? $\endgroup$
    – Black
    Commented Oct 11, 2014 at 16:32
  • $\begingroup$ The land could have got there in the case of a sufficiently large asteroid impact - a raised centre is a common feature of craters in a lot of places. The Yucatan is full of caves where the impact of the Chicxulub meteor hit. How those would drain to the ocean is a somewhat trickier question, but this setup might offer the kind of environment you are describing. $\endgroup$
    – glenatron
    Commented Oct 12, 2014 at 21:26

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