Inaccurate?

Acid Rain

(Heroes of Battle)

Conjuration (Creation) [Acid]
Level: Sorcerer 5, Wizard 5,
Components: V, S, M,
Casting Time: 1 standard action
Range: Long (400 ft. + 40 ft./level)
Area: 20-ft. radius cylinder, 40 ft. high
Duration: 1 full round and 1 round/level; see text
Saving Throw: None
Spell Resistance: No

You create a downpour of acid that douses the area for 1 full round, dealing 7d6 points of acid damage to every creature in the area.
The ground within the area becomes muddy and/or slick from the downpour, and remains in that condition for a number of rounds equal to the caster's class level.
Movement in the area is halved, though a creature can move at normal speed by making a DC 10 Balance check.
Failure on the check means it cannot move in that round, and failure by 5 or more results in the creature falling prone.
Material Component: A flask of acid (cost 10 gp).