Chances are, you’ve never seen anything like this captured photo of a fire rainbow before in your life.
Fire rainbows aren’t actually rainbows and they have nothing to do with fire, either. These so-called “fire rainbows” are actually known as circumhorizontal arcs and can occur when the sun has risen higher than 58° in the sky. is an optical phenomenon that belongs to the family of ice halos formed by the refraction of sun- or moonlight in plate-shaped ice crystals suspended in the atmosphere, typically in cirrus or cirrostratus clouds. In its full form, the arc has the appearance of a large, brightly spectrum-coloured band (red being the topmost colour) running parallel to the horizon, located far below the Sun or Moon.
There is a popular misconception that such halos are rare. However, their frequency depends on location in particular latitude. In the United States, it is relatively common to see them several times each summer, while the phenomenon is quite rare in mid-latitude and northern Europe. So, for example, the potential for these “fire rainbows” to form in Los Angeles is 5-10 times higher than in London.
Other currently accepted names for the circumhorizontal arc are circumhorizon arc or lower symmetric 46° plate arc. The misnomer, “fire rainbow” is sometimes used to describe this phenomenon, although it is neither a rainbow, nor related in any way to fire. The term, apparently coined in 2006, may originate in the occasional appearance of the arc as “flames” in the sky, when it occurs in fragmentary cirrus clouds.
Circumhorizontal arcs, especially when only fragments can be seen, are sometimes confused with cloud iridescence.
This phenomenon also causes clouds to appear multi-coloured, but it originates from diffraction (typically by liquid water droplets or ice crystals) rather than refraction. The two phenomena can be distinguished by several features.
Firstly, a circumhorizon arc always has a fixed location in the sky in relation to the Sun or Moon (namely below it at an angle of 46°), while iridescence can occur in different positions (often directly around the Sun or Moon). Secondly, the colour bands in a circumhorizon arc always run horizontally with the red on top, while in iridescence they are much more random in sequence and shape, which roughly follows the contours of the cloud that causes it. Finally, the colours of a circumhorizon arc are pure and spectral (more so than in a rainbow), while the colours in cloud iridescence have a more washed-out, “mother of pearl” appearance.
Photographer Cessna Kutz captured a magnificent fire rainbow over Lake Sammamish
“Witnessed a pretty cool phenomenon out on lake Sammamish today,” Cessna writes on her Instagram upon sharing the mesmerizing shot. “A horizontal rainbow! To me, it was a little reminder to hold onto hope and love instead of fear and panic in these unknown times. Stay safe out there, friends.”
It’s one of the most breathtaking sights we’ve seen recently, and we hope to share the positive vibes and inspirational natural beauty of this world.