What are some of the environmental factors that produce areas of precipitation extremes, such as rain forests and deserts?

One environmental factor that produces precipitation extremes is the proximity to large bodies of water. For instance, in order for there to be large amounts of precipitation, such as in a rainforest, the rainforest must be located near a large body of water, such as a lake. A desert lacks precipitation because it is very far from large bodies of water. Another factor that effects the amount of precipitation is elevation. Higher elevated lands typically receive more precipitation than lower elevation areas.