On the backside of the hill where I walk there is a hollow of shrubs in the middle of conifer forest. The hollow falls in a shallow V from a ridge, and it serves as a cold air duct. The cold winds that sweep along the ridge from the west slip into the duct to shoot over this hollow. In early spring, snow persists here despite the absence of trees. In fall, the hollow harbors the warning of winter. A chill gust of cold now comes down the slope’s duct. This afternoon, when temperatures have reached into the 50s, I find the morning’s frost persists in the hollow. Small plants, still green where they are protected by taller, dry grasses that insulate the margin of the trail, are rimmed by ice crystals. The edges of leaves have jagged and glistening constructions that seem almost like metal. I put the back of my fingers against the icy leaves and feel the sharp sensation of the coming winter.