Bows and other weapons can loose their projectiles a high-arcing volley. Even warriors who cannot see the foe can contribute to the attack by following suit to their friends.
Weapons with this rule allow the unit to fire with all models within range in the Shooting Phase as long as at least one model in the unit can drawto the target. However, if they do so, they suffer -1 To Hit. A unit cannot Volley Fire if it moved earlier in the turn or if the target is within half the weapon's maximum range.