The extreme terrain of California suprises many newcomers as to how different one part of the state looks to another. Below is a general overview on elevation pertaining to most California landscapes. Western mountain slopes are greener & get more moisture from the west (Pacific Ocean), plus the first rains of a storm. The lower altitude, coastal foothills can get a lot of moisture, especially during winter months. The Eastern slopes are drier and face the desert (Great Basin). Desert Mountain regions are quite different. Most dry ranges are in the "rain-shadow" of the taller Sierra Nevada mountain range and get little moisture.