Wind wall

Wind wall was an evocation spell that created a curtain of window to repel ranged weapons, disperse gases, and blow away small birds.

Effects
The spell created a curtain of wind, 2 feet (0.6 meters) thick and at least 150 feet (46 meters) long, or more for more experienced or capable casters. It stood vertically, but could otherwise take any continuous path, such as rectangular or cylindrical to protect the area inside. It lasted at least half a minute, or longer with experience. It was invisible, very sturdy, and comprised a roaring gust of wind.

This could blow away flying creatures smaller than eagles, preventing them passing through the barrier. It could whip papers and such from a person's hand if they were unprepared, and loose items and clothes were propelled upward. It blocked gases, creatures with gaseous forms (but not incorporeal creatures), and many kinds of gaseous breath weapons entirely. It deflected arrows and bolts upward, while heavier ranged weapons had a 1/3 greater chance of missing; hurled boulders, siege-engine projectiles, and so on were of course too heavy.

Components
It required verbal and somatic component. The divine version required a divine focus, while the arcane version required a tiny fan and a feather of an exotic creature as a material component.

History
This spell was developed by Netherese arcanist Tolodine as Tolodine's wind wall in, early in the history of Netheril.

Notable Appearances
In 1364 DR, Robillard, resident wizard of the Sea Sprite, discovered to his chagrin that the spell had virtually no effect on cannon-fire, probably because cannonballs are too fast and too dense.