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Saturday, June 23, 2007

Fire Rainbow

From the National Geographic archives.

June 19, 2006—It looks like a rainbow that's been set on fire, but this phenomenon is as cold as ice.

Known in the weather world as a circumhorizontal arc, this rare sight was caught on film on June 3 as it hung over northern Idaho near the Washington State border.

The arc isn't a rainbow in the traditional sense—it is caused by light passing through wispy, high-altitude cirrus clouds. The sight occurs only when the sun is very high in the sky (more than 58° above the horizon). What's more, the hexagonal ice crystals that make up cirrus clouds must be shaped like thick plates with their faces parallel to the ground.

When light enters through a vertical side face of such an ice crystal and leaves from the bottom face, it refracts, or bends, in the same way that light passes through a prism. If a cirrus's crystals are aligned just right, the whole cloud lights up in a spectrum of colors.

This particular arc spanned several hundred square miles of sky and lasted for about an hour, according to the London Daily Mail.


Fusion said...

This rare event haunts me. It took place on June 3rd of last year, and during that hour, had I walked out of my frickin house I would have seen it right overhead!


My son the meteorologist was really disappoint he missed it.

Princess of the Universe said...

I love when you post photos Fiona- they're always so beautiful!

kimba said...

oh - I was so about to say.. "Fuse is gonna wet his pants over this post.."

But i see he already has.. :)

Jonas said...

There are miracles all around us, every minute of every day. I wish I had better eyes...

Nish said...

Simply amazing.

Fiona said...

Oh Fusion, what a shame! You must have been kicking yourself for missing something like that which occurred overhead!!

Princess - thank you, I do try ;)

Kimba - are you sure you want a man who is incontinent ;) Just kidding Fusion. Cleanup on aisle 5?

Jonas - there really are, and sometimes we just don't take the time to look, even when our sight is good :)

Nish - hiya! Isn't nature awesome :)

Fusion said...

*shaking head*

I don't know which one of you is worse! ;)

Fiona said...

Looks innocent and points at Kimba...she is *L*


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