This process is called saltation, and it's a key mechanism in the transportation of sand by wind.
Here's a breakdown:
* Smaller particles (silt and clay) are too light to be lifted by wind, and they tend to be carried in suspension.
* Larger particles (gravel and pebbles) are too heavy for the wind to move effectively.
Saltation is where the wind's energy is just right to lift and bounce these sand-sized particles, creating a "rolling" effect along the surface.
