D&Dtools1

At your verbal command, the air nearby whirls and rises, carrying loose dirt and small objects into the air to pelt your foes.
This spell functions as gust of wind (PH 238), except as noted herein.
Instead of a path of wind, you create a whirling mass of air.
The whirlwind carries sand, dirt, and other small objects (nothing heavier than a chicken egg) into the air, creating an opaque cloud of debris.
Creatures must succeed on Fortitude saves as described in the gust of wind spell to avoid being checked or moved by the spell.
Creatures blown over or moved by the wind are pushed in a random direction.
The flying debris causes 1d4 points of bludgeoning damage per caster level (maximum 10d4); this damage is subject to damage reduction, and creatures are allowed a Reflex save for half damage.
If the debris is primarily composed of soft or very small objects, such as loose soil, the spell deals 1d4 points of damage per two caster levels (maximum 5d4).
The spell deals damage to objects within the spread, though hardness will usually negate this damage.