The same dampness that grows algae down the north side of a roof in Edmonds, the kind Puget Sound Softwash spends most weeks washing off with a low-pressure rinse, is exactly what turns to a stubborn skin of ice on the same shaded slopes once the temperature actually drops. The crew already knows which roofs, which driveways, and which north-facing walkways around town hold moisture longest, since that's the whole basis of the regular washing routes. On a snow day, that knowledge points straight at the spots most likely to ice over first — the shaded sides of houses set close under mature trees, the driveways that never quite catch afternoon sun even in summer. Washing equipment stays parked; shovels and ice melt go out instead, worked along those same problem areas rather than every driveway in town equally. A walkway that's damp and shaded in July is the one that's ice in January, and the crew treats that pattern as read rather than guessed. By afternoon, the shaded spots are caught up with the sunnier ones, at least until the next damp morning starts the whole cycle over.