Wind is the primary factor for causing ripples in the surface of desert sand but water can also be an agent during the rainy season.
I think the answer is called ripple marks
Small hills of sand made by the wind in a desert are called sand dunes.
Sand dunes
wind creates ripples in the sand
Dunes and desert pavement are both features of arid landscapes. Dunes are mounds of sand shaped by wind, while desert pavement is a surface covered with closely packed small rocks. Both formations are created by wind erosion and are common in desert environments.
Sand dunes in the desert are typically caused by the wind carrying and depositing sand particles. As the wind moves across the desert, it picks up loose sand grains and deposits them into dunes over time. The process of erosion and deposition continuously shapes and reshapes the dunes in response to the prevailing wind patterns.
loose dirt is blown by wind and because there is nothing to hold down the sand it is blown with the wind....oh!
Wind erosion is the primary cause of erosion and transportation of sediment in a desert environment. Strong winds pick up and carry loose particles, creating features like sand dunes and deflating the landscape.
Desert pavement does not move unless it is carried away by a flash flood. However, the wind can remove sand surrounding the sand in desert pavement.
Wind moving sand causes dunes, both in the desert and at the beach.
Wind or sidewinder.