Frosty artwork was on display when I opened my front door this morning. Random shapes and lines with intricate strokes adorned the storm door. Several inches of snow had fallen on the Horicon Marsh by this morning making the air moist. Our 9 degree morning temperature cooled the glass on the door to a temperature past the dew point. The dew point is the point where air gets so cold that water vapor in the air turns to liquid. If it is cold enough, like this morning, we get to see ice crystals when the liquid freezes on the glass.
The light and dark areas were created by a snow covered Colorado Blue Spruce Tree in the background. The surface of the window influences the pattern that is formed. Scratches and streaks of residual window cleaner affect the design.