As far as the US is concerned, there are no stricly "bad" locations for solar. Even using them in Alaska makes sense.

As long as you don't mind constantly removing snow from the panels, hopefully not damaging them in the process.

At these latitudes the optimal slope is 40+ degrees which is pretty steep by roof standards. I don't know how much of an issue it is in practice.

Snow and ice. Deep snow, deep ice. Layers of ice, then snow, then ice, created within a couple hours. I think even if it slides off, that could cause some damage.