> What's the term for a patch of land that has become a desert, because a mountainrange has blocked precipitation?And the answer: rain shadow. Photo credit: Gordon Wiltsie via National Geographic[https://www.nationalgeographic.org/encyclopedia/rain-shadow/].In a rain shadoweffect, rain and snow can occur on one side of a mountain, but on the other sideof the mountain, it's warm and dry. The Tibetan Plateau is an example of a rainshadow, where the enormous Himalayas block moisture from entering Tibet andChina.Rain shadows are dry areas on the backsides of mountains. As all tall structuresdo, the mountain creates a shadow, yet in this case it's a shadow of dryness. Tocreate this effect, a climate needs three essential elements: the ocean, wind,and a mountain range to block the air. Evaporation on the surface of the ocean creates moist air, while winds push thewet air inland until it reaches the base of the mountains. The air is forced torise, and as it does, it expands and cools. Cooler air can't hold as muchmoisture, so clouds form and rain pours down. The result? A lush green landscape– on one side of the mountain, at least.The now-dry air mass crosses the mountains, and begins to sink on the leewardside. As it falls, it compresses and warms, promoting evaporation. Dry air warmsone degree Celsius per one hundred meter of elevation drop. Some of the driest places in the world exist because of the rain shadow effect.A rain shadow creates arid land west of the Great Dividing range in Australia,east of the Sierra Nevada mountain range in California, and even southwest ofthe tropical Mauna Kea in Hawaii. Though, that's not to say the effect is whollydetrimental. Without the condensation of moisture on the mountainside, manylandscapes would be devoid of lush forms of life that call these regions home.