Grenade storm acts like a grenade at first, but upon landing, it summons a large swarm of mini-grenades. Finally, a large but regular grenade falls from the sky. in order for this to be effective, the enemy must be in a large depression.
Pros: A well placed level 3 grenade storm can do approximately 140 damage to an enemy, sometimes more.
Cons: Unless your target is not in a large depression, the mini-grenades will bounce uselessly everywhere, and you might hit friendly tanks.
A lot of luck is involved in this weapon