I’ve now observed a few weeks of snow on the roof. So far no ice dams and very few icicles…just what has resulted from the sun melting snow at the fringes of the exposed roof.
The snow slid off one section of the roof (the northeast corner, strangely). It was pretty dramatic when it went. We had a few quite warm days last week (around 35F/2C) and I think the ventilated roof actually allowed melting at the roof surface when warm air vented up through it. The snow bars above the hot tub are working very well.