Tuesday, August 2, 2022

Rainbow clouds

  

Some of you might recall that we observed some iridescent clouds last summer (see the post called "Iridescence in the air?" from 7 June 2021).  Around noontime today (2 August 2022) we saw something similar but a little differentdramatic "rainbow clouds" over Bodega Bay.  I think this is officially called a circumhorizon arc.

At first we noticed an unusual cloud lit up with blue and violet:

 
 
But then more colors started appearing elsewhere, extending horizontally across very high thin clouds:
 
 
Note that the colors appear in bands following a rainbow pattern, i.e., red/orange/yellow/green/blue/violet.

I'm not an expert, but I read that in iridescent clouds the colors are generally paler and random, while in circumhorizon arcs the colors can be quite bright and are organized in a classic rainbow color pattern.
 
Here are two photos showing closer views:
 
 
 
 
 
 And two more highlighting some interesting features:
 
 
 
 
Apparently circumhorizon arcs can appear when there are ice crystals in cirrus clouds and the sun is high (> 58°) above the horizon.
 
Sure made for a dramatic lunch!
 

3 comments:

  1. I'm simply speechless, Jackie.
    Oh how I wish I'd been there in person to see this magnificence and also hear the waves and smell the air.
    wow!

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  2. Thanks, Alice!

    Those lighting effects were pretty spectacular. I've read that rainbow clouds aren't necessarily rare, but I don't think I've seen anything quite like that before. Guess it's worth looking up when there are high cirrus clouds around, especially when the sun is high in the sky (around mid-day).

    :) Jackie

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