I was awed by this photo for a couple reasons. 1) It's a shot of the Old Faithful Geyser taken in landscape mode (instead of the tall portrait mode), and 2) the incredible side-light hitting the tower of water with the dark clouds providing a purple contrast in the background. Stunning. I've communicated with Lynn, the photographer, and here is what she had to add about the shot.
The photo was taken July 21, 2005 during a family vacation at Yellowstone National Park. The time was 8:05pm.