Translations:Adventist Youth Honors Answer Book/Nature/Weather/18/en
From Pathfinder Wiki
4. Why is it possible to be rainy on one side of the mountain range and dry on the other? Give an illustration for your country or region.
a. Why is it cooler and more moist in the mountains than in the lowlands?
b. From which direction do rain and clear weather usually come in your locality?
This wave cloud pattern formed off of the Île Amsterdam in the far southern Indian Ocean, due to orographic lift of an airmass by the island, producing alternating bands of condensed and invisible humidity downwind of the island as the moist air moves in vertical waves and the moisture successively condenses and evaporates.
Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it expands and cools. This cooler air cannot hold the moisture as well as warm air and this effectively raises the relative humidity to 100%, creating clouds and frequently precipitation.
