roof flowing in winter?

Hole in roof. Must find hole. Fix it. Possibly with tin of tar-based patch from Home Depot.
Maybe need new roof.

Ice dams. Your Quebec neighbours should be able to tell you exactly what to do. Like maybe, "Move to Antigonish."

Ice dams on your roof because of poor insulation. Water backs up underneath the shingles. Increase insulation or remove the snow after it falls each time.

Use rope access service.

Pour a bucket of FlexSeal onto your roof. Spread with an old boom.

Call a roofer to fix it. Winter is coming.

Could be the rubber seal on your roof from an exhaust fan.

You have a roof leak, pretty simple. What isn't so simply is finding the cause, could very well be ice damns. But ice damns form from a number of reasons, not just insulation but ventilation also lays a role. Ventilation can also play a role in condensation in an attic area, that can then melt and show symptoms like a roof leak. Of course with any water of this type, mold is soon to follow. But for that mold, it usually takes a bit of time, usually doesn't form when it's a one in done water situation.