Wall of Wind

Area
Surrounds an area with a wall of roiling air that impedes movement.
The wall is one yard thick and four yards high, but may be made higher by multiplying the cost as you multiply the height (double for 8 yards high, triple for 12 yards high, and so on). Low-tech missiles are buffeted off course as they cross it, and suffer a -10 penalty to hit for every yard of wall they pass through. High-tech bullets suffer a -2 penalty to hit for every yard of the wall of wind they pass through.
Beings standing within the wall’s thickness are at -3 DX and suffer 2d of knockback in a random direction every second.

The wall also churns up loose ground material, such as dust, small leaves, insects, and twigs. Each second, beings crossing the wall or standing in it must either shut their eyes or roll vs. HT to avoid being blinded, as per a one-point Sand Jet (unless the GM rules that the area is very clean, with no debris to circulate).

Duration: 1 minute.
Base cost: 2. Half that to maintain.
Time to cast: The wall appears as soon as the casting starts, initially surrounding a one-yard-radius area; the caster may move the perimeter outward at a rate of one yard of radius per second of concentration.
Prerequisite: Shape Air.

Item
Staff, wand, or jewelry. Usable only by mages.
Cost to create: 400 energy and a $500 onyx.