• rain shadow
    The Sierra Nevada block wind and weather systems from reaching Death Valley.

    Photograph by Gordon Wiltsie

    Can't Catch a Break
    (or a Raindrop)

    Death Valley faces a double-whammy of being located in the rain shadow of the Pacific Coast Range AND the Sierra Nevada. This is why Death Valley is one of the hottest, driest places on Earth.

    A rain shadow is a patch of land that has been forced to become a desert because mountain ranges blocked all plant-growing, rainy weather. On one side of the mountain, wet weather systems drop rain and snow. On the other side of the mountain—the rain shadow side—all that precipitation is blocked.

    In a rain shadow, it’s warm and dry. On the other side of the mountain, it’s wet and cool. Why is there a difference? When an air mass moves from a low elevation to a high elevation, it expands and cools. This cool air cannot hold moisture as well as warm air. Cool air forms clouds, which drop rain and snow, as it rises up a mountain. After the air mass crosses over the peak of the mountain and starts down the other side, the air warms up and the clouds dissipate. That means there is less rainfall.

    You’ll often find rain shadows next to some of the world’s most famous mountain ranges. Death Valley, a desert in the U.S. states of California and Nevada, is so hot and dry because it is in the rain shadow of the Sierra Nevada mountain range. The Tibetan Plateau, a rain shadow in Tibet, China, and India has the enormous Himalaya mountain range to thank for its dry climate.

  • Term Part of Speech Definition Encyclopedic Entry
    air mass Noun

    a large volume of air that is mostly consistent, horizontally, in temperature and humidity.

    Encyclopedic Entry: air mass
    climate Noun

    all weather conditions for a given location over a period of time.

    Encyclopedic Entry: climate
    desert Noun

    area of land that receives no more than 25 centimeters (10 inches) of precipitation a year.

    Encyclopedic Entry: desert
    elevation Noun

    height above or below sea level.

    Encyclopedic Entry: elevation
    mountain range Noun

    series or chain of mountains that are close together.

    precipitation Noun

    all forms in which water falls to Earth from the atmosphere.

    Encyclopedic Entry: precipitation
    rain shadow Noun

    dry land on the side of a mountain facing away from prevailing winds.

    Encyclopedic Entry: rain shadow
    snow Noun

    precipitation made of ice crystals.

    weather Noun

    state of the atmosphere, including temperature, atmospheric pressure, wind, humidity, precipitation, and cloudiness.

    Encyclopedic Entry: weather
    weather system Noun

    movement of warm or cold air.

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