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How can mountains create rain shadows?

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A car drives along the Trans-Canada Highway with Mount Sir Donald's sharp, snow-capped peak rising above forested slopes in the Selkirk Mountains, British Columbia. — mountain Mount Sir Donald in the Selkirk Mountains, British Columbia, looms above a segment of the Trans-Canada Highway.

Mountains create a rain shadow by acting as a physical barrier to moving air masses, a process closely linked to orographic precipitation.12

When moist air encounters a mountain range, it is forced upward. As this air rises, it cools, which reduces its moisture-bearing capacity and leads to the formation of clouds and heavy precipitation on the windward side of the range.13

By the time the air crosses the mountain ridge and begins to descend on the leeward side, it has lost much of its moisture. Furthermore, as the air descends, it undergoes adiabatic warming, which increases its capacity to hold moisture and inhibits cloud formation. Consequently, the area on the leeward side receives significantly less rainfall, resulting in a dry region known as a rain shadow. This effect is often responsible for creating semiarid or desert conditions in areas located downwind of major mountain barriers.43152