Ice Backup Solutions
        (Items 1 -4 do not address actual leak source, only the size of the ice jams)
1.)
 Envelope entire attic with proper level of insulation
This will decrease the size of ice jams.
2.)
Properly ventilate your attic. Attics with poor insulation  
are very difficult to ventilate, unless power solutions
(fans) are used.
3.)
Heating Cables. (Melt ice jams at gutter lines). These
are inefficient in severe storm situations.
4.)
Pull down snow, before ice jams appear.
5.)
Attack the source of the leak by proper installation of   
waterproof underlayment (ice guard) in problem areas.
In extreme situations, following manufacturer and building
code guidelines on ice guard may still result in ice backup situations.
Solutions are to increase area covered in ice guard, and
address items 1 and 2.