Carter E. Gowl Landscape Photography

Moments before sundown in the northeastern quadrant of Yellowstone National Park – early July. This was the most severe weather I’ve ever experienced below treeline. Within seconds after photographing this image I was knocked off my feet by a microburst. My 10 pound tripod with a Nikon F3T attached traveled 20 feet through the air. This was only a break in the storm. I had been so intent on capturing this scene that I neglected to look to the rear to see what was coming. The Alexander’s Dark Band between the primary and secondary rainbows is a phenomenon first described by Alexander of Aphrodisias in 200 AD. Light rays being reflected in the raindrops form the primary rainbow and brighten the sky inside it. Rays reflected twice form the secondary rainbow and brighten the sky outside. Raindrops along lines of sight between the two bows cannot transmit light to the eye, and, therefore, the sky is darker there.