Ice Damming killing roof decking.

This is how to kill off a roof. Buy a house with poor insulation in the attic. the proper way to stop Ice from damming is properly insulate the attic to where no heat can escape from the living area below. This example is from the back to back blizzards in Maryland.
If you plan on buying a house look for adequately insulated attics. The soffit vents must not be obstructed from blow in insulation. when inspecting look for water damage along the gutterline. Look behind the fascia board that the gutter attaches to. Inspect the attic for proper insulation. It should be deep and not just covering the floor of the attic. I have seen more than enough attice where the insulation mightjust cover the ceiling joists. Again make sure the soffit vents from inside the attic are blocked off from insulation so the air can breathe.