I am currently designing a world for a series of short stories and have started looking at what kind of weather patterns would be present in certain regions. For simplicity's sake, we can assume the planet is very earth-like.

I designed a mountain range that runs west to east. To the north of the range are icy and snow plains and in the south lies the rest of the continent. There is a small bay of ocean water to the west of the mountain range (roughly a third of the size of the Hudson Bay in North America). I would like runoff from the mountains to form a river which travels west to east at numerous points. The mountain range comes out to roughly 60 degrees north latitude, around the border of the Ferrel and Polar cells. I did some research online and used the following information to make an assumption:

1) The area around the polar front has high precipitation.

2) There is a noticeable temperature difference between the opposite sides of the polar front.

3) The polar front moves South during the Winter and North during the Summer.

4) The rain shadow effect.

The assumption: During the Winter, the polar air moves South and hits the mountains. The air rises and causes snow. The land to the South of the mountains see little rainfall as a result and the river dies down. During the Summer, the air from the body of the continent moves North and rise up the South side of the mountain causing rain and the snow in the mountains melt. Both contribute to the river, causing a flood plain further downstream. The land to the North of the mountains become drier. This progresses slowly during the other seasons of the year.

Is the information I am using correct? Is this assumption sound? If it isn't, then what would the climate around this mountain range actually be and could there be a location that has the type of climate I've described?

Thanks in advanced and I really appreciate the help!

EDIT: I've included a rough draft map of the continent. It is by no means complete and includes basic features I would like to include (I have done little to no research or forest or desert formation, but comments are welcome). As a reference of size, mountains 1 are at 60 degrees north latitude and desert 1 at 30 degrees north latitude. In region Alpha, I plan another mountain range running along the dotted line the triangle is on. In region Bravo, I would also like to place another forest (likely pine) south of mountains 1. Forests 1-4 are planned deciduous.

The map: http://imgur.com/icVxGAr

  • $\begingroup$ Sounds a lot like Alaska's Brooks Range: en.wikipedia.org/wiki/Brooks_Range $\endgroup$ – jamesqf Feb 26 '15 at 3:35
  • $\begingroup$ @jamesqf Thank you, at first glance, this region does look similar. I will look into it when I get the chance. $\endgroup$ – Leon7C Feb 26 '15 at 15:02
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    $\begingroup$ @Leon7C - Might want to read a little on continent formation and plate tectonics. Mountain ranges are going to form when two landmasses collide...Mountain 1 looks like a subcontinent (northern half of bravo) pushed into the main continent and formed a mountain range (maybe extend the mountain range to the sea?)...this is good. The second set of mountains is a bit harder to explain..maybe volcanic? I'll update my answer for you, I suspect mountain 1 will work as a wind funnel and isolate the northern climate from the south $\endgroup$ – Twelfth Feb 26 '15 at 18:46
  • $\begingroup$ Thank you for all the ideas, I was planning to look into this next. I suppose I have on question about forming mountain 1 that way: would that area be subject to earthquakes as a result? $\endgroup$ – Leon7C Feb 27 '15 at 21:48

There's a few issues here that might not give you the intended effects...my knowledge is a little more specialized with the north and south running mountains as the globes rotation drives the winds. The east vs west orientation of this makes is a bit different...air would be pushed east west across it and the end effect might be the northern air becoming completely isolated from the southern air on the other side of the mountains.

1) The area around the polar front has high precipitation.

This is one half of the equation. The area around the polar front is warm moist air mixing with cold air that creates precipitation. So you need that source of moist air to create precipitations. Where does the warm wet air come from, and how does it move over the mountain to come into contact with the polar front? If the warm and wet air gets pushed up over the mountains, it may well lose most of it's moisture before coming in contact with the full polar front, no?

3) The polar front moves South during the Winter and North during the Summer.

Will it? This is the part I'm having problems seeing...for it to move south, it would have to go up over a mountain range and back down the otherside.

I end up having the vision of two very seperate weather systems forming. On the north side, the wind would rush along the mountains East to west (polar easterlies) and then loop back west to east futher north. On the south side, you'd have winds that travel East to West further south, and then the circle of the winds East to west along the mountains. Er..or reverse of that.

With East west mountain orientation, I guess the main part that I'm not sure on is what would drive the air to move south/north over the mountain range...or would it remain two separate cycles independent of one another instead?

  • $\begingroup$ This is a very interesting concept that you propose as I failed to imagine the air currents in complete three dimensions. I have edited my original question to include a map, depicting some additional features, including oceans. Hopefully, this will provide some insight. $\endgroup$ – Leon7C Feb 26 '15 at 15:18

You mentioned there was a bay in the west but you never mentioned if there was an ocean somewhere.

about your assumptions:

  1. Yes, and I should add than places at high latitude are usually cold enough to stay humid even with little precipitations. Think like in Siberia for example.
  2. Yes but it is constantly changing. It alternate between cold and hot fronts, bringing precipitation and affecting the temperature. Keep in mind that the front is a wave moving around the Earth. It's not static line, it bends.
  3. Yes, 60 degrees north is probably the maximum extent of the front. Maybe 30 degrees north during the summer is the minimum.
  4. Yes, the mountain could block the winds if they are tall enough.

The rest: In winter, the poplar front is far to the south, beyond the mountains.In Siberia and Mongolia , it is very cold and dry during the winter. Some places receive almost nothing in precipitation like Pyongyang. It's like the Mediterranean climate but in a cold winter. But if your continent is smaller, like North America, you can still expect to have snow. It gradually decreases as you move away form large bodies of water (because that's where the water come form). The norther side would have little precipitations in winter but a moderate amount in summer.

Would the area south of the mountain be dry? It depends. If there is a large water body like an ocean not too far south: it's probably a temperate climate. Otherwise, where would the water come from? Or, if there is a large ocean in the west/east: large precipitations along the coats and decreases gradually when moving away form the coasts.

So, if there is a source of water not too far (in fact, it can be quite far if the land is flat) The south would probably be temperate with a moderate amount of precipitations in summer and winter.

The snow wold only melt partially , in the lower altitudes. At this latitude, areas over 1000m or 1500m over sea level will always be covered with snow.

Edit following the world map you provided:

Your continent reminds me a lot of Asia, except that it's larger and located closer to the pole. It would be affected by something similar to the Siberian high during winter, causing dry weather over large parts of the continent.

You should expect to have a monsoon during summer in the south. The effect could go as north as forest 1. This also makes desert 1 implausible because it's affected by the monsoon too. It might be hot enough to be some sort of savanna.

  • $\begingroup$ I've added a rough map of my continent with some additional information. This should give you an idea of where the oceans are and some things I have planned. I would also like to ask about the polar front descending to such a low altitude; is this because of the tilt in the Earth's axis? $\endgroup$ – Leon7C Feb 26 '15 at 15:13

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