Roger's SkyPix

Visual Effects

Double Rainbow over the Great Plains

Double Rainbow over the Great Plains

After observing a weak, anticyclonic supercell from near the Kansas-Colorado line, we made a slow tour around its E, S and W sides, seeing some nonsupercell tornado action from separate convection along the way. Here, along the back side of the storm, the late afternoon sunshine lit up its shield of trailing rain in the form of one of the grandest double rainbows I've seen. Notice the reverse order of colors in each arc -- with the blue-purple hues on the outside of the outer bow but along the inside of the inner one. In the inner rainbow, sunlight reflects once from the inside of each raindrop. The outer bow appears in its position because some sunlight reflects off the inside of individual raindrops twice before reaching your eyeballs. The red and blue-purple ends of the visible light spectrum move through the drop at different angles, and their rays cross each other when reflected twice in each drop. That reverses their order of appearance in the outer versus inner bow. Inner bows always are brighter than outers because less sunlight is left after the first reflective bounce from raindrops.

3 N Kit Carson CO (19 Jun 8) Looking ENE.

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