Ice dams are always caused by warm air beneath the roof deck. The problem is not your overhang, it's above it. There snow melts, then runs down to the eaves and freezes, then backs up under the shingles.

Retrofitting attic insulation and putting an ice and water shield type product on the entire roof deck before shingling are possible solutions for the future. For now, I'd avoid any sort of electrical device and give the metal belts a try. They should help considerably if they receive some direct sun exposure. (There is a bit of danger from falling ice to consider). It's difficult work, but using a roof rake from the ground to remove snow can also make a difference.

Yes,yes - roof has a low pitch. attic is insulated as best it can be (some areas can't be), ridge/soffit vents are in place, along with 12' of Ice/water barrier (which unfortunately, might have some places where they nailed -through- the boards (sigh)). Where the ice falls isn't a problem. I know I could rake, or do ice wires, but I prefer a passive solution (i'm too old to be raking 8-])

thanks!
/j

Insulation will not address the air loss unless you have a thick blanket of cellulose or spray foam.

The attic needs proper air sealing and I would be willing to bet your ice damning issues will drop to nil.

Spray foam sealing of all the top plates, bypasses, ductwork, and other air leakage locations will go a long way.

Even with a low slope roof, you can spray foam that outside top plate in most cases and get a good enough R-Value on it that the attic ventilation will take care of any radiant heat loss.