On a still January morning the Grand River smokes — freezing fog lifting off the open water below Riverside Park and settling as rime on every rail and windshield in reach. Mr Bill's Land Tree Snow works those mornings, plowing drives and lots along the river's north stretch, clearing the walks by hand, and putting salt where the fog has left a film too thin to see. The river keeps the air a few degrees warmer and the pavement a good deal slicker, and treating for that is its own particular skill. Snow here often arrives wet and heavy, the kind that has to be moved before it sets up like mortar. What gets left behind is bare pavement, which is the only outcome that counts.