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, plus the first rains of a storm. The lower altitude coastal foothill mountains can get a lot of moisture. The Eastern slopes are drier and face the desert. Desert Mountain regions are quite different. Most dry ranges are in the "rain-shadow" of the taller Sierra Nevada mountain range and get very little moisture.