Stunning 'Fire Rainbow' Formed by Halo of Ice

A so-called fire rainbow filled the sky with a haze of colors over South Carolina on Sunday (Aug. 16) in a recent photo posted to Twitter.

The alluring photo, snapped by Jackie Hill (though there was some debate about who took the photo after Tiffany B. Jenks first posted it to Twitter and claimed to have taken it) in the city Isle of Palms, shows what looks like a V-shaped rainbow of colors painted in the sky. The image gained worldwide attention, possibly for it's nontraditional take on a rainbow. However, the term fire rainbow — referring to the phenomenon's colorful, flamelike appearance — can be misleading, said J. Marshall Shepherd, the director of the Program in Atmospheric Sciences at the University of Georgia in Athens. This is because the halos of light have nothing to do with fire or rainbows, and form when sunlight hits ice crystals rather than raindrops.

The phenomenon is called a circumhorizon arc. The smoky-looking ice halos appear only when the sun is at least 58 degrees above the horizon, Shepherd said.


http://www.livescience.com/51915-fire-rainbow-south-carolina.html