Wind-blown sand grains travel in four distinct ways.

Saltation is the movement of particles by leaping or bouncing across the ground. (Saltation comes from the Latin saltare which means 'to leap'.) The grains are ejected from the ground, moved forward and given energy by higher wind speeds above the ground, and gradually descend back to the ground. Most saltation takes place within 30 cm (1 foot) of the ground, although small grains in strong winds can reach heights of 1.5-2 m (7-9 feet). Hop-lengths may be 12-15 times the height of the bounce. Saltation is the key process in sand movement because it powers all the other processes.

Reptation (from the Latin reptare: 'to crawl') is the low hopping of grains splashed up by descending high-energy grains. A saltating grain dislodges about 10 reptating ones when it hits the surface. These grains move only short distances.

Creep refers to grains travelling close to the surface by rolling and other small movements. Coarser particles--too heavy to be ejected into saltation or reptation--move by creep. This category also includes low-energy movements of smaller particles.

Suspension is the movement of particles that are literally carried by the wind--they follow the turbulent pathways of the wind and may be carried high above the ground. In general, only the lightest and smallest particles (dust) travel in suspension. The sand grains in the photos (above) are too heavy to travel in suspension. Sand can enter suspension briefly when wind-blown sand is transported over the tops of high dunes.