What wind speed is needed to start moving medium-sized sand grains?

To initiate the movement of sand grains, the wind velocity near the surface must exceed a specific threshold value, which varies based on the size of the grains. According to research on sand dunes, a wind speed of 12 km per hour (measured at a height of 10 metres) is required to move sand grains that are 0.02 cm in diameter, while a wind speed of 21 km per hour is necessary to move larger grains measuring 0.06 cm in diameter.1

Once this threshold is met and sand movement begins, it can be sustained by winds blowing at lower speeds. Additionally, because instantaneous wind speeds within turbulent eddies can significantly exceed average velocities, turbulence plays a critical role in the transport of sand, though it remains difficult to measure precisely.1