What is a 'fire rainbow?' Hint: it's not a rainbow, and it's not caused by fire
Residents of South Carolina鈥檚 Lowcountry witnessed an unusual natural light show on Sunday. A 鈥渇ire rainbow鈥� appeared in the sky and drew comparisons to 鈥渁 multi-colored angel鈥� for about an hour before disappearing,
Images of the iridescent clouds went viral, but scientists say 鈥渇ire rainbow鈥� is a misnomer: the phenomenon is not a true rainbow, and it has nothing to do with fire 鈥� instead of rain or flame, the phenomenon is caused by ice.
Meteorologist Justin Lock told Live 5 News several variables must coincide for the spectacle to appear. The sun has to be at least 58 degrees above the horizon, and it has to shine through high-level cirrus clouds, which are made of little ice crystals.
"To produce the rainbow colors the sun鈥檚 rays must enter the ice crystals at a precise angle to give the prism effect of the color spectrum," Mr. Lock said.
Lock also said the same phenomenon can explain colorful sunsets: when the sun is low, the light reflects and refracts through crystals in high-level cirrus clouds, giving off the bright, warm shades of red and purple we see.
The term 鈥渇ire rainbow鈥� was apparently in Spokane, Wash. in 2006. Circumhorizontal arcs 鈥� the real, if less catchy, name 鈥� can many times be seen during the spring and summer months in middle-latitude locations, saying that the spectacle looks 聽鈥渁s if wispy cirrus clouds take on a rainbow palette.鈥�
Perhaps the most memorable time a 鈥渞ainbow鈥� 鈥� real or false 鈥� went viral was in 2010, when a spotted near Yosemite National Park was posted and called possibly the by late night talk show host Jimmy Kimmel.
AccuWeather meteorologists say a when light bounces off the back of raindrops twice, may appear behind the 鈥減rimary鈥� rainbow, causing the double rainbow effect. The order of the second rainbow鈥檚 colors gets inverted, so blue is on the outside and red on the inside, rather than vice versa.
Tracey Smith saw Sunday鈥檚 fire rainbow from Isle of Palms, S.C. and captured the photo that went viral, in which the rainbow seems to resemble angel wings, WCSC-TV reported. She said it reminded her of a friend who had passed away.
"I'm sure she came to visit us on the beach we all love! We miss you Leslie!" she wrote.
