Boulder gives a lot of its snow back within a day — a chinook comes over the ridge, the temperature climbs thirty degrees, and the drifts along North Broadway are running water by lunch. Then the sun drops behind the foothills and all that meltwater turns into the real hazard. Green Thumb Snow Removal, Inc. works this season and only this season, and knows both halves of it: plowing drives and lots, shoveling walks and steps down to the surface, and putting ice melt where refreeze is a certainty rather than a risk. Storms here can show up in October or in the middle of April, so the trucks stay ready long past the point where that seems reasonable. Come morning the pavement is clear and the walk can be taken at full stride.