The leeward side of a mountain, also known as the rain shadow, is typically desert-like or semi-arid due to a phenomenon called the rain shadow effect. Here's a breakdown:

1. Moist Air Rises: As moist air from the ocean or other sources encounters a mountain range, it is forced to rise.

2. Cooling and Condensation: As the air ascends, it cools. This cooling causes the water vapor in the air to condense, forming clouds and ultimately leading to precipitation on the windward (upwind) side of the mountain.

3. Dry Air Descends: The air that has lost much of its moisture then descends on the leeward side of the mountain.

4. Adiabatic Warming: As the air descends, it is compressed, causing it to warm. This warming reduces the air's relative humidity, making it very dry.

5. Reduced Precipitation: The dry air that descends on the leeward side holds very little moisture, resulting in minimal precipitation and creating a dry, desert-like environment.

In short: The rain shadow effect creates a stark contrast between the wet, lush windward side and the dry, arid leeward side of a mountain range.

Examples of Rain Shadow Deserts:

* Great Basin Desert: The Sierra Nevada Mountains block moisture from the Pacific Ocean, creating this desert.

* Patagonian Desert: The Andes Mountains create a rain shadow effect, leading to the dry conditions of this desert.

* Gobi Desert: The Himalayas play a significant role in the formation of the Gobi Desert.