Final answer:
The rain shadow effect occurs when there is arid conditions on the leeward side of mountain ranges, as moist air loses its moisture upon ascending and subsequently descending the mountains, leading to semi-desert climates in the lee areas.
Step-by-step explanation:
The rain shadow effect refers to a climatic phenomenon where arid conditions are created on the leeward side of mountain ranges due to the loss of moisture from air masses as they ascend and descend over the mountains. This happens because moist air from the ocean rises up and over the mountain range, cools and its water vapor condenses, leading to precipitation on the windward side. The now dry air continues over the crest and descends on the leeward side where it warms up, leading to less moisture and precipitation, therefore, causing semi-desert conditions or a type B climate.
Places like the Hawaiian island of Kauai, the southwestern side of Puerto Rico, the western United States, and regions like western China and northern Chile all experience dramatic variations in climate because of the rain shadow effect. For instance, while the southern side of the Himalayas receives extensive monsoon rains, the rain shadow caused by these towering mountains results in arid conditions for western China. Similarly, the Cascade ranges in the United States create a rain shadow that leads to semi-arid conditions in eastern Washington and Oregon.