Rain shadow

A rain shadow is a dry region on the surface of earth that (with respect to the prevailing wind direction) is leeward or behind a mountain. A rain shadow area is dry because, as moist air masses rise to top a mountain range or large mountain, the air cools and water vapor condenses as rain, falling on the windward side or top of the mountain. This process is called \norographic precipitation. The effect of the process is the creation, on the leeward side, of an area of descending dry and warming air, and a region that is quite arid. Good examples (in the United States; rain shadows occur worldwide) are in the deserts of the Basin and Range Province, or the dry areas east of the Cascade Mountains of Oregon and Washington State. The apty-named Death Valley is another good American example; it is behind both the Coastal Range of California and the Sierra Nevada range, and is one of the driest places on Planet Earth.

External links and references

• Graphic showing how a rain shadow works\n*USA Today on rain shadows\n*Weather pages on rain shadows