skylight causes roof ventilation problem

Skylight ventilation problem. I have a converted attic that is a living space and it has a skylight. I live in Ontario Canada and keeping ventilation in the roof is important so the roof is cold and does not cause ice dams. I am getting ice dams below the skylite at the overhang. I don't think the person that installed the skylite added a way for the air to move around the skylight. Picture this. The whole roof has frost on it except all the area below the skylight down to the where the overhang begins and it is 2 feet wide.
I just bought the place last fall and it is an old downtown apartment duplex so I don't have the history of it. there is a power vent installed in the attic. The attic is only 4 feet high by umm 12 feet wide approx.
My question is this. Can I just add a roof vent below the skylight? Skylight is 2/3 up the roof

Thanks

 

Bud will be along shortly with a more succinct answer, but it does sound as if the insulation in the two bays below the skylight are blocked from air movement which is absolutely necessary to keep the roof at the same temperature all over.