The caster summons a storm. This spell must be cast outdoors. The storm will be a dust storm or sandstorm in an arid region, or a rainstorm otherwise. The storm is not dangerous to structures or living things, but will impart Concealment 1 to all creatures within it. This increases to Concealment 2 if it the Spell is Sustained, and to Concealment 3 if it is Sustained again.

When the caster ceases to sustain the spell, the storm begins to subside. At the beginning of each round, roll a d10. If the result comes up showing a 1, the storm will lose one level of Concealment. When it has lost all levels of Concealment, the storm ends.