Storm of vengeance

Storm of vengeance is a conjuration spell that calls a vicious thunderstorm that rains acid, thunder, and hail.

Effect
This spell creates an enormous black storm cloud. Lightning and crashing claps of thunder appear within the storm. Creatures beneath the cloud must succeed at Fortitude saves or be deafened (see blindness/deafness) for 1d4 x 10 minutes.

If you do not maintain concentration on the spell after casting it, the spell ends. If you continue to concentrate, the spell generates additional effects in each following round, as noted below. Each effect occurs during your turn.
 * Second Round: Acid rains down in the area, dealing 1d6 points of acid damage. No save is allowed.
 * Third Round: You call six bolts of lightning down from the cloud. You decide where the bolts strike. All may be directed at a single target, or they may be directed at up to six separate targets. Each bolt deals 10d6 points of electricity damage. Creatures struck can attempt Reflex saves for half damage.
 * Fourth Round: Hailstones rain down in the area, dealing 5d6 points of damage (no save).
 * Fifth through Tenth Rounds: Violent rain and wind gusts reduce visibility. The rain obscures all sight, including darkvision, beyond 5 feet. A creature 5 feet away has one-half concealment (attacks suffer a 20% miss chance). Creatures farther away have total concealment (50% miss chance, and the attacker cannot use sight to locate the target). Speed is reduced by three-quarters. Ranged attacks within the area of the storm are impossible. Spells cast within the area are disrupted unless the caster succeeds at a Concentration check against a DC equal to the storm of vengeance's save + the level of the spell the caster is trying to cast.