This is a total guess, but It looks like gases are escaping/leaking from between the can and the cone, kind of like an exhaust leak on a header. The base of the can looks like it's getting pretty hot where there are gases leaking. In fact, you can see flames shooting past a gap between the two components. That can't be right. I don't think there is a gasket, have you checked the torque on the cone fasteners?