Wind Erosion
1. SUSPENSION: Fine particles less than 0.1 mm in size are moved parallel to the surface and upward into the atmosphere by strong winds. The most spectacular of erosive processes, these particles can be carried high into the atmosphere, returning to earth only when the wind subsides or they are carried downward with precipitation. Suspended particles can travel hundreds of miles.
NASA satellite image of a dust storm carrying particles off the coast of west Africa. Image by NASA
2. SALTATION: Movement of particles by a series of short bounces along the surface of the ground, and dislodging additional particles with each impact. The bouncing particles ranging in size from 0.1 to 0.5 mm usually remain within 30 cm of the surface. Depending on conditions, this process accounts for 50 to 90% of the total movement of soil by wind.
3. SOIL CREEP: The rolling and sliding of larger soil particles along the ground surface. The movement of these particles is aided by the bouncing impacts of the saltating particles described above. Soil creep can move particles ranging from 0.5 to 1 mm in diameter, and accounts for 5 to 25% of total soil movement by wind.
The impact of bouncing soil particles dislodges finer particles into suspension and sets coarser particles into motion as surface creep. Image by UNL
In the following animation, you will observe the processes of saltation, surface creep, and suspension. Note that the larger particles tend to move by saltation and surface creep while finer particles are suspended and moved in the air. Click on the picture to view the animation.
The following two video clips (part I and part II) demonstrate different types of wind erosion and the relationship of soil texture to the types of wind erosion.