When a clipper drops down out of the northwest, Roseville hears it before it sees it — the wind comes across flat ground with nothing at all to slow it, and by midnight the drives have gone white again. Northern Skies Property Services is out under that sky, plowing, shoveling steps and walks, spreading salt where the freeze-and-thaw turns a slope of concrete into a rink. In the green half of the year the same trucks handle mowing, trimming, edging and seasonal cleanups. Either way, the measure is a property you can walk across without ever thinking about it. Coverage runs through Roseville, Fraser, Clinton Township, Warren and St. Clair Shores.