At the right time of day during the right time of year, the sun sets an shines down the river, lighting up the spray from the falls and creating a rainbow. This is one of my favourite view points of this set of falls because of the ferns in the bottom right and the moss that helps frame the scene.
Great picture, thanks for sharing! I like how the fallen trees lead your eyes around the frame to the rainbow. I wish the rainbow was a little less exposed to bring out a little more color, but otherwise really neat picture.
How lucky is this! Beautiful. I do agree with Shawn about the rainbow. good job!