Since the snow load can be a factor here, I decided against a sloping shed roof and built one with a central 2x12 ridge and clerestory vents oriented to the prevailing wind. The roof vents don't collect snow and are spring-loaded with thermal pistons and cable to open them.
The clerestory vents were supposed to be larger, but the builder who help me frame it thought that the original 2x10 ridge wasn't strong enough.
