Soffit vents sound like a good solution but I don't think we can use them on our house. We don't have any eaves so there is no place to put soffit vents! The rafter ends are cut flush to the side of the house. There is a horizontal board nailed to the end of the rafters and the gutters are attached to this board.
Making things worse is the fact that the ceiling on the top floor is sloped near the edge of the house meaning that it follows the roof line -- kinda like a partial cathedral ceiling, if that makes sense. I am not sure how to get outside air to flow in this space on the lower 2 or 3 feet of the roof (where the rafters double as ceiling joists), which is where the ice damming occurs.
The house is masonry and it was built in 1938. There has been no rotting or decay, so something works. With no vents it sure is hot up in the attic on a sunny day!
I'm not sure whether I explained the construction clearly enough... Thanks agin. :-) --Dawn