Fire cloud

By Phil Plait | July 6, 2006 11:27 pm

Bad Reader Eric sent me a note about an email going around about a very pretty atmospheric phenomenon called, in the email, a "fire rainbow". It’s actually called a circumhorizontal arc. It’s caused by sunlight refracting through ice crystals in the air, much like rainbows and haloes.

The Snopes page linked above quotes an email going around saying this is "THE RAREST OF ALL NATURALLY OCCURING ATMOSPHERIC PHENOMENA" (yes, the original email was shouting). I don’t think that’s true, since I’ve seen this several times. I think the Parry arc is rarer; I’ve only seen one twice in my life. Ironically, one was when I was in grad school at the University of Virginia during a big football game; the arc formed a giant "V" in the sky, which we all got a kick out of– though not so much the football team, which was humiliated by Georgia Tech. So much for omens in the sky!

CATEGORIZED UNDER: Astronomy, Cool stuff, Time Sink

Comments (27)

  1. Eighthman

    It’s kinda sad that people can’t just enjoy an interesting photo without some self-appointed caption writer making exaggerated claims. I read the Snopes article two days ago and was peeved by the “rarest” claim.

  2. ToSeek

    I’ve seen plenty of them – I’d say they’re more common than rainbows.

  3. Looks cool, but I have never seen it myself.

    Have seen some fantastic rainbows though, including some that made people pull their cars over to get out for a better look.
    Camera’s left back at home, of course.

  4. in a strange coincidence, i saw my very first one just this week. It was spectacular, and i very nearly drove into the car in front of me in my efforts to keep looking at it.

    In retrospect it was one of those moments that make me really treasure my science education. I saw an awesome physical phenomenon, and the fact that i understood how it was caused didn’t make it less amazing. In fact, it made it made it more amazing. I’ve never got why some people think that understanding how the universe works makes living in it any less of an exciting, surprising, wonderful experience.

  5. Michelle Rochon

    It’s not quite rare. I see a lot of these “fire clouds” ūüėõ Most of them I see when I wear sunglasses though, like I do to see lots of sunrays. I can see paler stuff more easily that way.

  6. J. D. Mack

    I’ll always remember the coolest rainbow I ever saw. After this rainstorm, the eastern sky was a *very* dark purple, and the sun broke through the clouds just moments after it had slipped below the horizon. The rainbow that appeared simply looked electric because there was far less ambient light from the sun than usual. At the time, I was on duty at my job at Walt Disney World. The rainbow looked so unreal that guests kept asking me if it was a special effect created by Disney.

    J. D.

  7. Eric

    awesome!! Thanks for posting this Phil!

  8. Eric

    Also, I’ve never seen a parry arc so yea, I guess that is rare!

  9. Tim G

    Rainbows are GAY!


  10. “Rainbows are GAY!”

    Because they rain men?

  11. Tim G


    Gay can mean a lot of things. Look at #3 in the most popular definition. I was kinda making a jab at homophobia.

  12. Tim G


    I picked up the phrase from a T-Shirt.

  13. Oh, I haven’t seen that T-Shirt, mine says: “I’m with Stupid” and my wife says: “You are 39 years old, GROW UP!”

  14. Dom

    I seen this in New Scientist. Pretty Neat.

  15. Paul A.

    Where can I get a wallpaper size image? I didn’t see one at the National Geographic website where this story came from.

  16. Ah hah! I knew it had something to do with ice crystals! I took a photo of a similar effect when I was up in Alaska a few years ago.

  17. Gail

    Have you really looked at this photo? I was curious about it and made it my wallpaper…it still is. But if you do that, and make it larger…look at it…REALLY look into the picture. To just a little left of the center…there is a head shaped from the clouds. I am not one of those who sees the virgin Mary in ‘whatever’, but I can see this face…looking down. Am I nuts?

  18. lendy

    i took this video 1-20-08 here in skien norway.not for sure if it is a circumhorizontal arc or what but it was awesome .i watched it with my bf for over 2 hours right before it got dark it finally went away.

  19. DANNY D


  20. Thank you for correcting the original mistake. I found this site by Googling the words “Fire Rainbow” because I was looking for the original photo to make a wallpaper from, as the idiot who made the version I received thoughtlessly had written over the image.

    I am an avid skywatcher but I have not seen one of these. I have seen sunsets cast a spectral glow on distant clouds in the west but nothing like this.

    I do agree with Moonflake, above, that our education in science allows us to appreciare natural wonders all the more, than say some ignorant primitive belief that a man in the sky is painting the clouds as a promise to mankind that he will not send a flood to wipe us out.

    Thank God for a good public school education!

    John Rosengarten
    Chicago, USA

  21. Al Mallette

    John – the text is Genesis 9 right after God had destroyed the living things on the earth: 8 Then God spoke to Noah and to his sons with him, saying,
    9 “Now behold, I Myself do establish My covenant with you, and with your descendants after you;
    10 and with every living creature that is with you, the birds, the cattle, and every beast of the earth with you; of all that comes out of the ark, even every beast of the earth.
    11 “I establish My covenant with you; and all flesh shall never again be cut off by the water of the flood, neither shall there again be a flood to destroy the earth.”
    12 God said, “This is the sign of the covenant which I am making between Me and you and every living creature that is with you, for all[8][Or everlasting generations ] successive generations;
    13 I set My bow in the cloud, and it shall be for a sign of a covenant between Me and the earth.
    14 “It shall come about, when I bring a cloud over the earth, that the bow will be seen in the cloud,
    15 and I will remember My covenant, which is between Me and you and every living creature of all flesh; and never again shall the water become a flood to destroy all flesh.
    16 “When the bow is in the cloud, then I will look upon it, to remember the everlasting covenant between God and every living creature of all flesh that is on the earth.”
    17 And God said to Noah, “This is the sign of the covenant which I have established between Me and all flesh that is on the earth.”

    God did it then and He did it for this picture – man could not even coordinate this event! Thank God for His power !!! Al Mallette

  22. ashley

    so ive seen about 3 in my life.. and im only 18!! i had my camera on me only once.. the other times i was in the car.. they’re very beautiful.. well.. keep your eyes to the sky and your camera nearby ūüėÄ

  23. Scott

    We were driving southwest through Virginia this past week, both wearing polarized sunglasses. In the afternoon there were many light high wispy clouds and the edges of many had pastel rainbows. This was after waking up to a beautiful 6-inch snowfall and watching an adult bald eagle flying around over a nearby lake as we shoveled our way out of the cabin. Rather a magical-feeling day.

  24. This past winter, I saw a rainbow in the clouds that didn’t go any farther. I guess that’s what you were writing about here :^ .

  25. I have been watching the sky for 40 years, and began taking photos of these clouds in 2008. This was not normal, never have I seen it before. This only happens after a series of military contrails, everyone laugh. I have documented the entire event three times, here is the latest one I put up on you tube.
    And it just happened again yesterday so I was thinking about doing it again I even got pics of these rainbow clouds in the lght of the full moon, I would like some scientific dodge to cover that and they were not nocturnal clouds it was complete nightfall with low vapor trails.


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar