A nor'easter puts the ocean on Revere Beach Boulevard — spray over the sea wall, sand across the pavement, and by morning the whole city needing to be dug out at once. Arrow Sweeping Inc runs that storm work: plowing lots and drives, clearing walkways and entrances, salting and sanding the ice that sets in behind the wind. Parking lots along Broadway have to be pushed and stacked so nobody loses a space they need, which takes some thinking as well as some steel. There is a plain satisfaction in a lot that is black and dry while the drifts stand along its edges. When the storm has gone through, the pavement gets swept clean and the city gets on with it.