← Same Sun, True Size · Lesson 3 of 3
The dry side of the mountain
When moist air blows into a mountain range, it is pushed upwards and cools. Cool air holds less water, so the moisture falls as rain or snow on the side facing the wind.
By the time the air comes down the far side it has lost most of its water, and it warms as it sinks. That side is dry: a rain shadow. California's Sierra Nevada is wet on its western side, and the dry lands of Nevada lie in its shadow to the east.
The wind blows from the west over a tall mountain range. Which side is likely to be driest?
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