Steam Fog

September and October are fog season. The longer, cooler nights and relatively warmer water often produce foggy mornings. I use to see this over Loch Raven Reservoir when I was flying in the helicopter every day.
Here is a pond at The Greens in Ijamsville. You can see the fog forming off of the warmer water just like steam rising from a hot bath. While it has not completely cleared out yet, it will soon.