The dunes are composed predominantly of light-colored quartz and feldspar, most likely eroded from the granitics of the San Bernardino Mountains to the southwest.

Kelso Dunes represent part of a much larger sand transport system, which includes the nearby Devils Playground region.

The composition and morphology of the sand grains indicate that most originated from the Mojave River sink near Afton Canyon, which lies to the west of the dunes' current location.

During dry climate episodes, a decrease in stabilizing vegetation exposed surface sand to wind erosion, which ultimately brought the sand to the dunes (most of the eastern part of the Kelso dunes was formed when nearby Soda Lake and Silver Lake dried into their current playas).

Enthusiasts sometimes climb to the top of the dunes and slide down slowly, generating a low-frequency rumble that can be both felt and heard.