14 DAY TRIAL // A few days ago, on August 16, a rare and positively gorgeous display of colors appeared in the sky over South Carolina, US. It only lasted for a few minutes, but people had plenty of time to gawk at it and snap pictures. Pictures that are now understandably making the rounds on social media.
Such displays are known to scientists as circumhorizontal arcs. Lay people, however, call them fire rainbows. This is despite the fact that they don't really have anything to do with rainbows or fire.
Rather, these so-called fire rainbows form in the sky when sunlight encounters plate-shaped ice crystals suspended in Earth's atmosphere, usually crowded together in clouds, and is refracted.
When passing through these ice crystals, the light is dispersed and comes out broken down into its constituent spectral colors. True, the same mechanism forms proper rainbows, except that these other displays of color involve water droplets and not ice crystals.
In an interview, meteorologist Justin Lock explained that, to form such fire rainbows, sunlight must reach the ice crystals suspended in the atmosphere at a precise angle. Otherwise, not much will happen.
“To produce the rainbow colors the sun's rays must enter the ice crystals at a precise angle to give the prism effect of the color spectrum. It has to do with getting the precise angle,” Justin Lock said, as cited by CBS News.
Without clarity. So beautiful A photo posted by Carole Rich Williams (@icrw70) on Aug 16, 2015 at 2:00pm PDT
Seen Off The NC Coast. #firerainbow #wow #saltlife #pineknollshoresnc #crystalcoast A photo posted by Roger Jennings (@3rdnlong) on Aug 17, 2015 at 3:11pm PDT
Life's a beach #charleston #rainbows A photo posted by Gino (@ginknowsabe) on Aug 16, 2015 at 11:53am PDT