From Glossary of Meteorology
A strong wind carrying sand through the air.
The diameter of most of the particles ranges from 0.08 to 1 mm. In contrast to a duststorm, the sand particles are mostly confined to the lowest 3.5 m (10 ft), rarely rise more than 15 m (50 ft) above the ground, and proceed mainly in a series of leaps (saltation). Sandstorms are best developed in desert regions where there is loose sand, often in dunes, without much admixture of dust. Sandstorms are due to strong winds caused or enhanced by surface heating and tend to form during the day and die out at night.