Stunning "Fire Rainbow" Captured Over California's Pinnacle National Park

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Photo Credit: Michael Jimenez via National Weather Service Bay Area facebook

Last week, a runner traversing the trails of California’s Pinnacle National Park encountered a mesmerizing sight — a halo of rainbow colors emanating from the single cloud in the clear blue skies. While the phenomenon is commonly referred to as a “fire rainbow,” researchers say the name is misleading since the optical illusion is neither a rainbow, nor does it have anything to do with fire!

Photo Credit: Michael Jimenez via National Weather Service Bay Area Facebook

Instead, the stunning halos are circumhorizon, or circumhorizontal, arcs, which only occur in the summer. They require two conditions — the sun has to be situated 58 degrees or higher in the sky, and there has to be the presence of cirrus clouds. The thin, wispy clouds, which can be found at high altitudes, exist in a low-temperature environment and are therefore filled with ice crystals. As the sun’s light passes through them, the ice particles act like prisms, creating the colorful illusion.

Image Credit: Les Cowley (

Since the sun has to be higher than 58 degrees in the sky for the natural phenomenon to occur, the likelihood of encountering one depends on where you reside. The further away a country is from the equator, the less amount of time the sun remains at the high altitude. Also, the frequency of the sunny days has to coincide with the presence of cirrus clouds. As a result, “fire rainbows” are relatively common in North American cities like Houston and Los Angeles, where they are spotted at least four to five times during summer. However, while they are occasionally seen in European cities such as London and Paris, circumhorizontal arcs do not occur in areas north of Copenhagen.


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  1. What did a runner recently see at Pinnacle National Park?
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“While the phenomenon is commonly referred to as a “fire rainbow,” researchers say the name is misleading since the optical illusion is neither a rainbow, nor...

  • Unicorn LandTuesday, December 18, 2018 at 9:36 am
    Soooooooooooo cool and pretty
    • straberry feetThursday, December 6, 2018 at 9:20 am
      that´s dope
      • lowkeyThursday, November 29, 2018 at 6:49 am
        thats really cool!
        • thinnestice7896
          thinnestice7896Thursday, November 22, 2018 at 8:42 am
          That reminds me of when I was watching tv one night. It was about science and it had a person on top of a mountain and it looked like there were 3 suns because of the refraction. Light is awesome, man.
          • olimpia5223
            olimpia5223Thursday, November 22, 2018 at 8:38 am
            That 's COOL 😎😎😎. I feel bad for the people who have lost their homes due to the 🔥
            • Lulusweet34 mspWednesday, November 21, 2018 at 6:12 pm
              That's awesome.
              • dragonfire13
                dragonfire13Wednesday, November 21, 2018 at 3:47 pm
                • Awesomeness_031Monday, November 19, 2018 at 12:11 pm
                  I know right this is the greatest thing i have ever seen. and ya it looks just like the tesseract.
                  • feona
                    feonaMonday, November 19, 2018 at 10:57 am
                    So beautiful!!!!
                    • xXxLitNerdxXxMonday, November 19, 2018 at 9:46 am
                      That was cool

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