this always had some issues. but i recall messing around with it and knew this would be cool if it worked right. i tried fixing this about ten years ago, finally got around to it again...xP
i fixed the bad inum call and the damage statement. works great now.
Code:
//Storm
storm_level 40
storm_cooldown 36
storm_time 12
storm_radius 600
storm_maxdamage 400