My favorite image from 11/27/12 3:53 PM MST. The rainbow clouds are technically iridescent clouds. It's diffraction, not refraction. I've seen these before, but not quite such a display. The winds were very high. The lenticular clouds were high in the stratosphere. f/8, 1/1250s, ISO 100, lens focal length 60mm.
I strongly believe this phenomenon is the unintended consequence of chemtrailing. I'm certain there will be skeptics. The public is mostly unaware of what is going on.