There is an hour in a Mahopac February, somewhere past three in the morning, when the hills go absolutely silent and the snow just keeps arriving. A&D Service Group is awake for it. Plow trucks work the steep driveways and switchback lanes that Putnam County is full of, then the walks get shoveled and the ice gets treated before anybody has to think about it. Storms come in off the Hudson Highlands with a lot of intent, and the answer is a seasonal route run start to finish, every time. The best part of the job is invisible: a driveway already open at six, the day going ahead as planned.