Tornado spell not spawning whirlwinds most of the time

Fixed in r2406 (part of Beta 10).

I tried to copy the code from the Iron Lich section of Vavoom and the spell sometimes does spawn a whirlwind that actually goes after monsters and hurts them, but most of the time it doesn’t spawn a visible whirlwind (might be out of sight, no idea). It also crashes fairly often.