Western Deserts Deserts are found in areas where evaporation exceeds precipitation. High incident solar radiation as well as wind add up to a negative water budget, meaning that deserts are always dry. Far from wastelands, however, deserts are teeming with life. The type of desert and its aridity depend on the timing and amount of precipitation. The nature of desert soil also affects availability of water for plant growth.
More rain can infiltrate sandy and gravelly soils than clay soils.
If rain comes as deluges, most of the water will not penetrate the soil but rather will run off the surface, and plants will receive little benefit. Many areas have saline or alkaline soils due to the constant evaporation of water, which brings minerals to the surface. Due to their position between tall mountain ranges and the influence of the cold waters of the Pacific Ocean, the western deserts are subject to dramatic seasonal shifts in storm tracks. In the cold northern Great Basin, most of the sparse annual precipitation falls as snow. The warmer deserts to the south receive their annual precipitation as rain, either in winter or summer.