I have been trying to shoot The Ohio River all winter when the stars align for the river to let off water vapor at dawn. I have only captured it accidentally with my cell phone, but I was dying to get my SLR out to shoot it. The best I can make out, the over-night lows need to be very cold, and the skies need to be clear enough at dawn for the sun to warm the surface of the river water. It was 5 degrees when I was shooting this morning, and I suspect this is the last time the river will smoke this winter. The vapor coupled with the jubilant early morning light is at once eerie and magnificent. It was worth losing feeling in my fingers.