Thanks for the advice finding41. Not just a great form for sailing advice!
That is the reason, ice dams and water coming in but I dont think its due to lack of ventilation.I have cathedral ceilings and skylights and by the looks of the dams built up just below the skylights, they have been melting the snow that lands on them and causing the dams. I do have insulated skylight covers to go on top of them but I didn't get them on this year because the snow came so early.
Next time you do the roof... (I know you want to hear this...)
Go all out and use the Ice and Water Shield all the way up from the eves. It will cost about $300 more for the average house but it won't ever leak again!
We used to have bad ice dams to the point of water leaking onto the window sills! (Not good for white linen curtains!) When I did my roof 2 years ago and used it for the first 6' form the eves. Then tar/ felt paper the rest of the way up. There used to be 3 vents. Now there are 7. (Read the instructions on a bundle of shingles and don't let a roofer NOT follow them. They won't want to put that much Ice Shield on because they won't ever be back...)
I also got into my attic and pulled the insulation away form the roof and trusses ware it touched. (Great job PO.) Then vacuumed out the < space so air could move. Then added another foot of fluffy stuff keeping it away from the edges.
(A couple years ago there was a insulation incentive form the Ont. government and a lot of my contracting clients took advantage of it. One problem was the insulation company's were growing so quickly they didn't train there guys not to fill the < space when they blew it in. Allot of peoples eves were ripped off there houses that winter by Ice dams! My clients included. I had my clients get there eves fixed for free by the insulation company's by showing the poor work and lack of care they took.)