West of the village the Black River runs cold and quick past Ralston, and by January its edges have glassed over while the middle keeps moving — which is roughly how a Mendham winter treats a driveway, freezing at the margins first. Black River Landscape Management Inc. reads that pattern for a living, plowing the storm as it falls, returning for the drifting, then salting the shaded curve the sun never quite reaches. Stone-walled lanes and steep approaches get the slow, careful pass instead of the fast one. Walkways are cleared by hand where a blade has no business going. When the overnight thaw-and-refreeze sets in, the treatment is down before anyone's boots find the slick spot.