I am currently in the process of building my fantasy world from the ground up and as I finished my height map, I realized I had some pretty tall mountains. Not just a few of those stereotypical lone, fantasy super peaks but rather entire chains that spanned thousands of miles. With average heights at around 40,000 ft. and the largest being 50,000+, this is obviously greater than any modern day and real world examples. The next step in my process is to determine wind currents. I've done what I feel is a good amount of research so far into the various cells and winds, the role of temperature and latitude, and so forth.

My questions are largely to do with what effects these high altitudes would have on global wind currents, assuming an Earth-like environment. It's my understanding that even some of the highest altitude winds (i.e. jet streams) could be blocked by the aforementioned heights in certain cases, so how should I factor this into my climate simulation? If we were to make these mountains EVEN taller to ensure they reach these high altitude winds, does it make a difference? Would these winds be deflected or would they simple flow higher in the atmosphere to compensate?

If I may ask another question in a similar vein, how does slope effect wind patterns? If we compare the stark incline of a classic mountain to something like Mars' Olympus Mons, which is tens of thousands of feet above "sea level" but comparatively flat, how would they differ? If we were to place the two in the same atmospheric settings, would the air density at the peaks be the same?

If you'd be willing to give a more targeted answer for my world, below is the height map.

enter image description here

As you can see, there are several large chains running vertically south of the equatorial sea, while the northern continent has a large elevated area that is more like a "blob" or plain (hence the Olympus Mons question)

I'd like to learn the cause and not just the effect for these things, so extended explanations are welcome. However, all answers, partial or full, are appreciated. Thanks!


An Eager Worldbuilder

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    $\begingroup$ Your jetstreams would behave more like earth's oceanic currents do, i.e. rotations within a bounded region, rather than jetstream-like rotations around the poles. But what the knock-on effect of this would be is way, way past my paygrade. $\endgroup$
    – PcMan
    Jan 3, 2021 at 11:07
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    $\begingroup$ I think that Bernoulli says that you will get very,very,very high wind speeds over that elevated plateau. Expect monster dust storms downwind from it, even if the rarified wind moves little air it will move much dust. $\endgroup$
    – PcMan
    Jan 15, 2021 at 19:24

1 Answer 1


Rain shadows (areas of desert on the landward side of a mountain range) would be much more pronounced. These areas form when mountains a) block weather systems from moving over them or b) force clouds passing over to empty out their precipitation via adiabatic cooling. So you're going to get very large, very dry deserts.


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