Can attic insulation be rolled over ductwork?
You can cover the ducts with more insulation -- just make sure to mark where they are, and provide a way for the HVAC tech to access any dampers, etal.

(Sidenote: given your location, an unvented, insulated compact roof could very well be a better bet -- this makes the attic part of the conditioned space, and eliminates the hunt for duct leaks.)