Look down the valley to the southwest and you'll see the white, mirage-like surface of Soda Dry Lake. Playa lakes are among the flattest landforms in the world. They form under arid conditions when water drains into basins with no outlet to the sea and quickly evaporates. Soda Lake lies at the terminus of the Mojave River. In wet years, the playa contains standing water. In drier times, water may lie very near the surface of the playa. Capillary action draws the water upward where it evaporates, leaving a white, puffy crust of evaporite minerals such as sodium carbonate and sodium bicarbonate.
During wetter climates, the playa lake basins of the Basin-and-Range province were filled with perennial lakes. At least twice, from 18,000 to 16,000 years ago and from 13,700 to 11,400 years ago, a long-lived lake, Lake Mojave, filled Soda and Silver Lake playas. Lake Mojave dried out by 8,700 years ago, becoming the playa we see today.