What are Those Colorful, Crazy Clouds in the Sky??

By Nancy Atkinson - June 27, 2014 at 11:49 AM UTC | Planetary Science
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My Twitter feed exploded on June 25 with reports of colorful, crazy-looking clouds, sundogs, Sun halos and more. The above image from

Nathanial Burton-Bradford

is just an example of the type of atmospheric effect called a circumhorizontal arc. These are sometimes referred to as "fire rainbows" but of course are not rainbows, and fire plays no role.

This is an optical phenomenon from sunlight hitting ice crystals in high cirrus clouds. It is actually a rather rare occurrence, but it happens most often during the daytime in summer when the Sun is high in the sky. This creates a rainbow-type effect directly in the ice crystal-filled clouds.

See more examples below.

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Wispy clouds and a circumhorizontal arc over Italy. Credit and copyright: Elisabetta Bonora.[/caption]

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Circumhorizontal Arc over the UK on June 25, 2014. Credit and copyright: Sculptor Lil on Flickr. [/caption]

You can find out more about circumhorizontal arcs from

this article from Amusing Planet.

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com