The WSA is an alluvium (loose soil shaped by water) and sand dune covered valley. The terrain consists of free-moving sand dunes, dunes stabilized by trees or brush, and sagebrush flats. Old juniper trees and changing shadow patterns on the dunes provide a variety of visual settings.A unique plant known as Atriplex canescens var gigantean grows in the WSA. It is a four-wing saltbrush that grows to 10 feet tall and appears to be the last relic community of a plant species that was once widespread.