This video, we're going to talk about how mountain ranges affect climate. So mountains can affect local climates by creating a barrier to airflow, essentially forcing the air to rise upwards into the atmosphere before it can proceed forwards. Now prevailing winds bringing moist air to mountains from one particular direction can create what's known as a rain shadow. And a rain shadow can be defined as a dry desert-like area on the leeward side of a mountain range. And the leeward side of a mountain range is really just the side that's opposite of the windward side, and the windward side as its name implies is the side of the mountain range that receives the prevailing winds.

And so in this image, notice that we've got this mountain range right here in the middle, and the arrows represent the direction of the prevailing winds. The red arrows represent warm air and the blue arrows represent cold air. And so in this image, we've got cold moist air approaching the land in this direction, and as it makes its way over the land, it heats up, which is why it turns red. Now as the prevailing winds make their way towards the mountain ranges, it's going to act as a barrier to the airflow and force the air to rise upwards into the atmosphere. And this rising air is going to cool down, which is why it turns blue again.

And the cooling air loses its ability to retain moisture, which is why it causes precipitation on the windward side of the mountain range, and that's why there's lots of vegetation on the windward side. Now as the prevailing winds make their way over the mountain, it's lost all of its moisture. And so now it's dry air, and as it descends downward, it will heat up, and that dry air will be able to absorb moisture from the land to create a dry desert-like environment on the leeward side, which is what we call the rain shadow. Now a classic example of a rain shadow is the one that's caused by the Sierra Nevada Mountains in California. So notice that on the windward side, we've got lots and lots of vegetation on this side, but then on the leeward side, we get this really large dry desert-like environment that we call the rain shadow.

So that concludes this video and I'll see you all in the next one.