Final answer:
When clouds pass over a mountain, the resulting rain shadow effect can cause one side to have abundant rainfall while the other experiences drier conditions due to the descending warm, dry air absorbing moisture.
Step-by-step explanation:
When clouds move to the other side of a mountain, they are subject to a meteorological phenomenon known as the rain shadow effect. As winds carrying moist air encounter a mountain, the air is forced upward and cools, causing the water vapor to condense and form precipitation on the windward side of the mountain. Upon reaching the summit and moving downwards on the leeward side, the now drier air descends, warms up, and absorbs moisture, leading to arid conditions and less precipitation in what is known as the rain shadow area. This process can create a stark contrast in climate and vegetation between the two sides of the mountain.