I'm attempting to construct a world such that a hot desert like the Sahara exists in the region outlined in yellow. world map with region of interest highlighted The same map depicting prevailing winds (thick arrows) and ocean currents (thin arrows) world map with prevailing winds and ocean currents I'm working under the following constraints:

  1. the desert must be located on the eastern half of the continent
  2. the desert must directly border the ocean to the south (it cannot be a solely interior desert)
  3. the desert should believably arise through natural means (geography/climate) and not artificially, such as via magic and over-farming

I've added a very tall mountain range (think Himalayas) to the east to produce a rain shadow effect, placed the region such that the prevailing winds will blow off shore, and oriented a cold ocean current on the western side.

Are these factors sufficient to produce a desert in this region, and how far could it reasonably extend? If not, what changes can I make to achieve this?

  • $\begingroup$ Re criterion 3 - does "natural" exclude all human / sapient activity, or can over-farming be a cause (eg the no-longer Fertile Crescent)? $\endgroup$ May 5 at 5:43
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    $\begingroup$ You mean, can the Arabian desert actually exist, or is it only a legend? $\endgroup$
    – AlexP
    May 5 at 8:30
  • $\begingroup$ @KerrAvon2055 I would prefer to exclude all sapient activity, such that the region contains little to no sign of major civilizations past or present. $\endgroup$ May 5 at 13:22
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    $\begingroup$ You said it yourself. There is a rain shadow. You got the circulation patterns worked out. Your clearly have a basic understanding of how to model the climate. Follow the Artifexian Youtube series or the Worldbuilding Pasta blogs guide. Show us the end result to critique. You got this, go ahead and do it. $\endgroup$ May 5 at 15:09
  • $\begingroup$ @TheDyingOfLight, you should post yours as an answer, and I'll vote for it. H0tCh0colate3 has done his homework, so the only real answer is "Yes". Still, it's a good question. $\endgroup$ May 5 at 19:25

3 Answers 3


because the trade winds are nearly parallel to the coast. Deserts outside the subtropical zone exist in the Horn of Africa. A near-desert exists in northeastern Brazil for much the same reason, although the coast itself has nearly-onshore winds in the winter (and a rare As climate).

Otherwise, the true deserts are in rain-shadow areas like Patagonia, the Gobi, Takla Makan, etc. Technically the Antarctic Dry Valleys are true desert due to precipitation (it would be snow!) shadows, and these desolate places even have ice-covered salt lakes.

The location would get moist winds off a sea and westerly storms, much like the southeastern USA, which is definitely not desert.


Most deserts are all at the same latitudes

If you look at a world map, you will see most of the big deserts are all at the same latitude as the Sahara (with a few at the southern equivalent). This is because the worlds Hadley Cells cause high pressure at these latitudes. This pattern will be true for any earth-like planet. So put your desert at that latitude, and combined with the measures you've already taken, definitely.

  • $\begingroup$ "Most of the big deserts are all at the same latitude as the Sahara": Except all those which are not. Antarctica, the Arabian desert, Taklamakhan, Gobi, the Great Australian desert ... $\endgroup$
    – AlexP
    May 6 at 15:25
  • $\begingroup$ 1) Hadley Cells and Horse Latitudes are real. There are deviations of a few degrees but the big desert band exists nonetheless. 2) The Arabian desert is. 3) The Australian desert is at the Southern equivalent. $\endgroup$ May 13 at 20:18

Deserts can happen anywhere

Deserts aren't a just places with little rain and a lot of sun. Deserts can happen anywhere for a multitude of reasons.

The easiest natural one is erosion. Through some damage to nature and then precious soil being washed away this can already happen. It can be as simple as a long drought and then suddenly a lot of rain.

With less vegetation able to take hold the ground more easily dies up, doesn't hold in to water and is washed away by rain. This can become a self strengthening spiral, creating a bigger and bigger desert.

The desert part will easily heat up in the sun, making for scorching dry sand during the day. It'll cool off rapidly at night as nothing holds the heat as well, making it doubly difficult to live there.

Depending on the latitude it can become a desert like we know, or gor example a mild empty wasteland, only relatively warm for the climate during the day and relatively cold in the night.


Desertification can happen anywhere for many reasons. As it can be triggered by many different kinds of unlucky events it is easy to explain it. It isn't easy to have a desert, but with millennia to form there are no reasons for there not to be a desert there.

Some examples just for fun.

Tsunami hit, removed a kilometer of vegetation, remaining salt made it barren for most vegetation. Further rain removed the soil and this kept eating at the fringes for a thousand years until everything became a desert.

A hurricane damaged huge swaths of firest. Together with a few years of high amounts of rain and it removed valuable soil.

An invasive species (plant, animal or bacteria) came to inhabit the area. It destroyed the ecosystem, pollination didn't happen fir most plants and died off, the remaining ones had too little to protect thenselves and were eaten or destroyed by weather.

Due to a global warming period some Algea in the ice in the antarctic died off. This was a major source of plankton food, of which many sea creatures relied upon. The mass death caused many creatures to die that migrate to that area as well. The lack of food caused some further important species to die off, causing some explosion of other creatures as their natural enemy was practically removed. These eat the whole area to such an extent it can't recover, leaving a wasteland. The remaining creatures eat away anything still trying to grow for a few years before nothing is able to grow there, as the climate has changed drastically.


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