When an ice dam occurs, the only corrective action that can be taken is to remove the barrier of ice at the gutter line or to remove the ice build-up on the roof area before it melts from underneath. It must be noted that working on a roof under these conditions is extremely dangerous. The risk of injury should always be weighed against the cost of water damage repair. Also, in removing ice from the gutter and roof, you may cause damage to these areas that will require professional repair. Again, the cost of water damage repair may be less than the cost of a roof or gutter repair.