The outdoor unit of a heat pump relies on air flow to operate properly at all times. Snow must be cleared from around the unit leaving a clearance of 2 to 3 feet minimum surrounding the unit. Heat pumps must be elevated off the ground to allow the water produced during the defrost cycle to flow away from the unit. Snow build up at the bottom few inches of the unit can prevent the unit from completing the defrost cycle properly. If the snow is not cleared, the unit will not function properly. If the system is operated under these conditions it has potential to damage a unit, even for only a short period of Time.