At four in the morning the cobbles on Johnny Cake Hill are blue-white and nobody is out but the plows. DEMELO & SONS, INC. runs those hours — pushing lots clean, opening driveways, cutting a path to the door before the first alarm clock goes off downtown. Wet coastal snow is heavy stuff, so the trick is timing: come through early, come through again, keep the piles where they will not be in the way tomorrow. Walks get shoveled and salted so nothing glazes over when the temperature slides after midnight. By sunrise the city looks like it simply woke up plowed, which is exactly the point.