What caused the colors that I saw in the clouds?

We have received several inquires about what appears to be rainbows which have been spotted in thin cirrus clouds. 

Most folks think of just one type of rainbow, but there are many types and categories including cloud bows, primary bows, secondary bows, red bows, reflection bows, sun dogs or moon bows (to name just a few).  I believe the folks inquiring may have spotted an iridescent cloud. 

This optical effect can produce bright spots, color bands or borders of colors.  This can occur when visible light from the sun is diffracted or “bent” by water droplets or ice crystals in the cloud. Sometimes iridescence clouds can be seen far from the sun. However, it is most frequently viewed when the sun is at a closer angle to the cloud. Remember to block the sun’s direct rays behind a building or tree to view iridescence safely.