Summoning up the power of the tempest, you direct a current of forceful winds where you please. This spell creates a 5-foot-diameter line of wind—the direction of the wind is away from your location when you cast the spell, and remains constant in that direction for the spell Duration. Creatures caught in a River of Wind take 4d6 nonlethal Damage and are knocked prone. A successful Fortitude save halves the Damage and prevents being knocked prone.

A Creature that begins its turn wholly or partially within a River of Wind must make a Fortitude save or be pushed 20 feet in the wind's direction of flow, take 2d6 nonlethal Damage, and be knocked prone—a successful Fortitude save means the Creature merely takes 1d6 nonlethal Damage. Creatures under the effect of Freedom of Movement and creatures with the air subtype are unaffected by a River of Wind.