1. areas lacking adequate moisture 2. strenuously cold climate. D. IVegetation destroyed by man. Herbicides, the plow, overgrazing.
Saltation is how sand particles move.
Farmers destroyed the vegetative cover of the soil. Dustbowl years that stripped away the soil by blowing wind. Nothing unusual in climate, just the destruction of the cover. A. Loess - deposits of dust sized particles. In the Midwest, one can see outcrops of this fine, unstratified material all over.