How do you get past the curse barrier behind the cannon at Wawku Shrine? I have destroyed the cannons and melted the wall to get the giant snow ball but I can't see what you do with it.

That isn't the bit I'm talking about. Further on outside you get to a ledge with four cannons which have to be fired in the right direction to destroy cannons on the other side of a gap, then you create ice platforms from the snow to cross the gap. There is another cannon which stops firing when you get close to the wall. I melted some snow stalagmites and a big snowball emerged. Behind the cannon is a cursed barrier, which I can't get past.