D&Dtools1

You create a duststorm or sandstorm.
Sandstorm uses the parameters of control winds (see page 214 of the Player's Handbook), differing from that spell as shown above and as follows.
A spellcaster who knows sandstorm need not be in an area of exposed, sandy soil to create the effects described below—
this spell conjures both sand and wind.
Duststorm Strength: For every three caster levels, you can increase or decrease wind strength by one level.
Wind speeds of less than severe are insufficient to carry suspended sand.
(Wind strength and related duststorm effects are briefly summarized below, with more detail found on page 16).
Each round on your turn, creatures in the area must make Fortitude saves or suffer the effects of being in the wind, as well as the effects of suspended grit.
A severe wind (31+ mph) causes minor ship and building damage, and creates a duststorm with fine grains of sand that reduces visibility, smothers unprotected flames, and even chokes protected flames.
A windstorm (51+ mph) drives most flying creatures from the skies, uproots small trees, knocks down light wooden structures, tears off roofs, and endangers ships.
Wind of this speed creates a sandstorm that badly reduces visibility and deals 1d3 points of nonlethal damage each round to anyone caught out in the open.
Hurricane force winds (75+ mph) destroy wooden buildings, sometimes uproot even large trees, and cause most ships to founder.
Wind of this speed creates a flensing sandstorm that severely reduces visibility and deals 1d3 points of lethal damage each round to anyone caught out in the open.
A tornado (175+ mph) destroys all nonfortified buildings and often uproots large trees.
Tornado-force sandstorms are of the flensing variety.