The Sierra Nevada mountain range creates a rain shadow effect on its leeward side, leading to drier conditions.

The Sierra Nevada mountain range causes a rain shadow effect on its eastern, or leeward, side. As moist air from the Pacific Ocean rises up the western slopes of the Sierra Nevada, it cools and releases precipitation, often as rain or snow. Once the air crosses the peak and descends on the eastern side, it becomes warmer and drier, resulting in reduced humidity and much lower rainfall. This process creates arid or semi-arid conditions in areas like Nevada and the eastern parts of California, shaping the landscape and limiting vegetation growth.