a semi-permanent accumulation of loose sand that forms in areas where the wind tends to blow in one direction, at velocities high enough to move sand, across a land surface that permits sand to amass in a regular and consistent form
The desert basins commonly have windblown sand. You may see small deposits of sand around plants, boulders, telephone poles, or anything that slows down the wind. A "sand dune" is any pile of windblown sand, but some in the Hueco Bolson are pretty big piles of sand. One of the interesting things about windblown sand is that most of the sand grains are all about the same size. Most winds are not strong enough to carry larger grains like gravel, but smaller grains, like clay and silt, are carried far beyond where the wind drops the sand. Sand dunes often have interesting patterns, like ripple marks, formed by the wind, and on a windy day you can often see how the wind makes sand dunes. Sand dune with ripple marks formed by wind.