Wind wall

Wind Wall is an evocation spell that deflects arrows, smaller creatures, and gases.

Effect
An invisible vertical curtain of wind appears. It is 2 feet thick and of considerable strength. It is a roaring blast sufficient to blow away any bird smaller than an eagle or tear papers and similar materials from unsuspecting hands. (A Reflex save allows a creature to maintain its grasp on an object.) Tiny and Small flying creatures cannot pass through the barrier. Loose materials and cloth garments fly upward when caught in a ['wind wall''. Arrows and bolts are deflected upward and miss, while any other normal ranged weapon passing through the wall suffers a 30% miss chance. (A giant-thrown boulder, a siege projectile, and other massive ranged weapons are not affected.) Gases, most gaseous breath weapons, and creatures in gaseous form cannot pass through the wall (although it is no barrier to incorporeal creatures).

While the wall must be vertical, you can shape it in any continuous path along the ground that you like. It is possible to create cylindrical or square wind walls to enclose specific points. A 5th-level caster can create a wall up to 50 feet long and up to 25 feet high, which is sufficient to form a cylinder of wind 15 feet in diameter.

Material components
A tiny fan and a feather of exotic origin.

Appearances
Wind wall is a popular spell for seaboard warfare, as it can deflect arrows, catapult and ballista shots from enemy vessels. However, in Passage to Dawn by R.A. Salvatore, Robillard, resident wizard of the Sea Sprite, discovered to his chagrin that the spell has virtually no effect on cannon-fire, probably because cannonballs are too fast and too dense. Fortunately for the Sea Sprite, Catti-brie was able to hit the cannon's smokepowder magazine with an arrow from Taulmaril, sparking an explosion that destroyed the enemy ship (and half the harbor with it).