Swan Lake was frozen enough to walk across today. I was intrigued by the bubble patterns shown in the photo. I don’t recall noticing any like that before. I wonder how they were formed. At least in one case it appears that bubbles were associated with a piece of vegetation that must have stayed below the bottom surface of the ice for a time. Perhaps the same is true of the other streak of bubbles, but the piece of vegetation there ultimately sank before being trapped in ice?