The term "fire rainbow" is misleading; while the phenomenon it describes is real, it is neither a rainbow nor related to fire. This atmospheric event is properly known as a circumhorizontal arc.
What is a Circumhorizontal Arc?
| Feature | Description |
|---|---|
| Misleading Term | "Fire rainbow" is a popular, but inaccurate term. |
| Correct Name | Circumhorizontal arc |
| Nature | An optical phenomenon, not related to fire or rainbows. |
| Appearance | A colorful, horizontal arc of light, sometimes appearing like "flames" in the sky. |
| Formation | Formed by the refraction of sunlight through ice crystals in high cirrus clouds. |
| Origin of Term | The term "fire rainbow" was coined around 2006, possibly due to the arc's resemblance to flames, especially when observed in fragments of cirrus clouds. |
Key Takeaways:
- Not a Rainbow: The circumhorizontal arc is not a rainbow. Rainbows are formed by the refraction and reflection of light in water droplets, while circumhorizontal arcs are formed by refraction through ice crystals.
- No Fire Involved: The term "fire" is entirely misleading; no fire or heat is involved in this phenomenon.
- Rare Occurrence: Circumhorizontal arcs are not very common. They require specific atmospheric conditions including a certain cloud type and the sun to be at a specific angle to the horizon.
Therefore, while the phenomenon referred to as a "fire rainbow" is a real optical phenomenon (a circumhorizontal arc), it is not a rainbow and is not related to fire.
