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How would just the weather be affected if there was huge mountain range between the Arctic and the mid latitudes of a planet? Roughly 50-60 degrees latitude. A little further south than Earth's Arctic circle at 66 degrees latitude.

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NOTE I am more than aware that climate questions always depend on the situation. But this is a worldbuilding site to help people build their worlds. That unfortunately includes the horrible 'too broad' climate questions. Please leave some comments if you need further information that I haven't supplied. I may not be aware of the important facts you may raise...which is why I'm asking!

I've included a portion of my map.

northern map the two horizontal black lines are 60 degrees latitude and 30 degrees latitude. red arrows - warm ocean currents, blue arrows - cold ocean currents, green arrows - prevailing wind direction (just general wind direction. I haven't made them follow the mountains yet - this was just a guide for me to figure things out)

As you can see my mountain range is currently further south than 60 degrees. This is because I still want some settlements north of the mountain range. therefore my prevailing winds are actually blowing onto the mountain range not flowing from it.

Height

  • I'm not talking Everest height here, more like the Rockies/Andes at about 3000 to 4500m above sea level.
  • I am aware that there are some mountains in the Arctic, but for this scenario they can be considered too small.

Orientation

  • Running horizontally west to east at about 50 - 60 degrees latitude.
  • The Urals run vertically north south in the northern hemisphere and the Andes, Rockies and Cascades all run pretty much north south as well. So there are no exact real life examples of the scenario I'm exploring.

Length

  • The mountain range in question wouldn't encircle the globe completely, but only run about 1/4 to 1/3 of the way around the 55 degree latitude line. The Arctic won't be completely cut off and isolated.

South of the mountains (I didn't want to give this information as I wanted a generic answer that others could use)

  • South of the mountains would be around 1500m to 1000m above sea level tapering down to the sea. It wouldn't be a high Plateau.
  • There is a large rocky desert immediately south of the mountains becoming a more sandy desert the further south you go to about 30 degrees latitude.
  • no large mountains running horizontally between the arctic mountains in question and the inland sea just south of the sand desert.

East and west of the mountains

  • Sea. Cold in the east, warmer on the west.
  • The Western mountain range would be very fertile and green.
  • The Eastern mountain range would also be green, but a lot dryer than the West. It would have lots of fog and low-lying mist.
  • both edges of the mountains would have massive storms. I haven't figured out which would be bigger/more dangerous yet.

North of the mountains

  • Small portion of land reaching to about 65-70 degrees latitude.
  • narrow frigid sea (strong current) before reaching the polar ice cap.

This is what I know

  • the mountains will block the cold winds from the arctic.
  • the snow will accumulate on the mountain range and some snowmelt may contribute to seasonal rivers into the desert.
  • the cold current in the east with prevailing onshore winds will result in dry conditions with little air moisture. (oops, just double checked and the prevailing wind direction is offshore. But the wind will be flowing all the way from the west coast, across the continent and be very dry by the time is reaches the East coast. There is a slight mountain range in the west to cause the water to fall on the coast. Therefore my 'little air moisture' comment will still stand)
  • Orographic uplift from the south shouldn't play too much of a role as the desert air is already dry.
  • The desert would be a lot warmer than an earth counterpart, as the cold arctic winds will not contribute to cooling.

Examples of other factors I'm not sure of

  • Will the orographic uplift north of the mountain range result in heavier snowfall than what you would expect on Earth at that latitude (this can affect my seasonal rivers fed by snowmelt)?
  • will the orographic uplift north of the mountains result in a more wet climate allowing more vegetation in the summer months?
  • will the cold mountain winds drag more cold air down from the high altitudes bringing cold air to my low lying desert region. Will it have enough time to warm adiabatically?
  • How will the arctic air pressure flow around the edges of the mountains. Will it be very stormy where the cold air flows into the warmer south?
  • what else am I not aware of?

I'm more curious of the impacts in the lower latitudes but don't mind answers focusing on either or both.

Obviously the mountains will affect the local weather dynamics and therefore affect the larger regional climate. But how?

If this isn't specific enough, please leave a comment and I will see if I have more information already figured out. If not, please leave an answer...it's why I'm here!

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  • $\begingroup$ Do you want something like connecting the Alps to the Himalayas? $\endgroup$ – Victor Stafusa Sep 28 '16 at 16:35
  • $\begingroup$ I believe that this question is too broad to answer. Changes in winds change rain and snowfall, changes in snow change albedo, and so on. Effects may be counterintuitive. $\endgroup$ – o.m. Sep 28 '16 at 17:38
  • $\begingroup$ Give me a few hours and I will try refine it down a bit. $\endgroup$ – EveryBitHelps Sep 28 '16 at 17:58
  • $\begingroup$ I've tried to narrow it down a bit by adding my world details. I was hoping for a generic answer that others could use but 'oh well'... $\endgroup$ – EveryBitHelps Sep 28 '16 at 20:18
  • $\begingroup$ I found a related question - but the map and answer provided ask for forest south of the mountain range. So I do not consider it a duplicate. worldbuilding.stackexchange.com/questions/10891/… $\endgroup$ – EveryBitHelps Sep 28 '16 at 21:11
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Mountains can block cold air flows from the north. Cold weather is in general caused by cold air cells building over northern continents (like Canada or Siberia) and then migrating southwards. The biggest effect of a high mountain barrier is to block this air flow. Once the cold air has passed over a mountain range heading south, the air will be adiabatically warmed as it descends (called katabatic winds).

Here are some examples of nearby cities, one blocked by northern mountains, and one not:

-Sanliurfa, Turkey (ancient Edessa) is at 37.09N, 477m elevation in a hot dry desert. It has a yearly average temp of 18.3 C, and summer average of 31.9 C.

-Ashgabat, Turkmenistan is at 37.56N, 219m elevation in a hot dry desert. It has a yearly average temp of 17.1 C and summer average of 31.3 C.

-In winter, Sanliurfa's mean temp is 5.6C, average low is 2.3 C. The mountains of the Armenian Plateau and the Caucasus block southwards moving cold air masses from the Central Asian steppes

-In winter, Ashgabat's mean temp is 3.5 C, average low is -0.4 C. There is nothing to block cold air from Central Asia.

Another:

-Boise, Idaho is at 43.37N at 830m in a cool, dry grassland. It has a yearly average temp of 11.3 C and a summer average high of 24.3 C.

-Rapid City, South Dakota is at 44.08N at 976m in a cool dry grassland. It has a yearly average temp of 8.5 C and summer average high of 22.6 C.

-In winter, Boise's mean temp is -0.4 and average low is -4.1. Boise is protected by the high mountains of the Northern Rockies. There isn't enough land area for cold air masses to form between the northern Rockies and the Pacific ocean.

-In winter, Rapid City's mean temp is -3.9 and average low is -10.6. Rapid City has no northern protection from the Arctic lows that form over northern and central Canada in the winter.

In general, note that the East coast of the US freezes every winter, all the way down to Atlanta where the average yearly low temp is -9 C. Seattle, on the other hand, almost 2000 miles north of Atlanta, sees an average yearly low of -4C. Northern California never freezes, yet South Texas does.

So the answer to your question is: if they are long enough, they can block cold air masses from moving south, leading to sub-tropical region like Southern California that never freezes, instead of a sub-tropical region like Louisiana that does. This changes the plants and wild-life: Trees shed their leaves in East Texas, but not Southern California. Monkeys live with evergreen trees in Sichuan, China, where they are protected from cold north winds, but not in Louisiana which is at the same latitude, because the trees there go dead in the winter, etc.

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  • $\begingroup$ So it almost certainly won't affect summer temperatures too much. And make winters slightly more bearable. I was thinking that the height of the mountain might pull high atmosphere air down into the southern 'interior'. $\endgroup$ – EveryBitHelps Sep 28 '16 at 17:15
  • $\begingroup$ I wouldn't say almost certainly. Mountains aren't the only thing affecting weather; two other very important effects are large bodies of water, and monsoon circulations. The Tibetan plateau causes the monsoon circulation in India, and the temperature swings of East Siberia cause the monsoon in China and East Asia. Your 60 N mountain range, if turned into a vast, high plateau, could cause a summer monsoon to the south. $\endgroup$ – kingledion Sep 28 '16 at 17:32

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