Rare 'fire rainbow' spotted in South Carolina sky

ISLE OF PALMS, S.C., Aug. 20 (UPI) -- For an hour on Monday, sky-watchers along the coast of South Carolina were witness to a rare meteorological phenomenon known as a "fire rainbow."

The colorful display was the result of sunlight hitting the tiny ice crystals that form high-altitude cirrus clouds at just the right angle. The sun must be between 52 and 58 degrees above the horizon and the cirrus clouds must be at just the right height. The result is a cloud colored by what are called circumhorizontal arcs.

"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," meteorologist Justin Lock told Greenville, South Carolina, news station WYFF. "Again, it has to do with getting the precise angle."

Tweeters posted a plethora of pictures, likening the shape of the wispy rainbow cloud to a whale tale or angel wings. The fire rainbow could be seen from the beaches of Isle of Palms, South Carolina, as well as Charleston.

A similar display was witnessed in Wisconsin earlier this summer.

"This is a rare sight at higher latitudes, where the sun is not sufficiently high above the horizon," Weather.com wrote of the display. "In the middle latitudes, however, the spring and summer months offer the best chance to see this."