What is a 'fire rainbow?' Hint: it's not a rainbow, and it's not caused by fire

Residents of South Carolina’s Lowcountry witnessed an unusual natural light show on Sunday August 16th. A “fire rainbow” appeared in the sky and drew comparisons to “a multi-colored angel” for about an hour before disappearing, The media in Charleston reported.

Rare "fire rainbow" goes viral after several sightings in S.C. http://t.co/g99uOh05nS pic.twitter.com/bAqs5jmCVv

— CBS News (@CBSNews) August 20, 2015

Images of the iridescent clouds went viral, but scientists say “fire rainbow” is a misnomer: the phenomenon is not a true rainbow, and it has nothing to do with fire – instead of rain or flame, the phenomenon is caused by ice.

Seeing lots of pics of the #IsleOfPalms #FireRainbow so thought I'd share mine! pic.twitter.com/0MDoJ5ogry

— Carrie (@carrie_brighton) August 20, 2015

The term “fire rainbow” was apparently coined by a journalist in Spokane, Wash. in 2006. Circumhorizontal arcs – the real, if less catchy, name – can many times be seen during the spring and summer months in middle-latitude locations, the Weather Channel reported, saying that the spectacle looks  “as if wispy cirrus clouds take on a rainbow palette.”

Perhaps the most memorable time a “rainbow” – real or false – went viral was in 2010, when a YouTube video of a “double rainbow” spotted near Yosemite National Park was posted online.

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