EarthSky // FAQs // Earth By EarthSky Jul 01, 2010

Why does the sky change color before a tornado?

No one knows for sure. But there are a couple of theories that suggest what creates the strange greenish-yellow color that can precede a storm.

No one knows for sure why the sky changes color before a tornado or severe thunderstorm. But there are a couple of theories that suggest what creates the strange greenish-yellow color that (sometimes) precedes a storm.

To understand the first theory, you’ve got to picture mountains. Mountains in the distance often look a deepening blue. That blue color stems from the scattering of light by air molecules – it’s the same reason the sky looks blue. Some experts think that, before a thunderstorm, golden-reddish light from the sun low in the sky and a natural bluing effect of the air combine to create a green sky. The storm provides a dark backdrop and offsets this greenish or yellowish hue.

A different meteorological theory holds that storm clouds themselves may help make the color of the sky bluish-green. To understand this theory, you first need to know that water is intrinsically blue (sometimes you can see the bluish tint of water in a white bathtub). It could be that the storm clouds — which are filled with water — provide the color blue, which, again, is illuminated by the golden light of a low sun to create the color green.

In sum: the reason for green skies before a storm isn’t entirely known. But it is known that a greenish-yellow sky before a storm is common in some parts of the world, while totally absent in others.

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8 Responses to Why does the sky change color before a tornado?

  1. Joshua says:

    My theory is based upon reflection. Prior to a tornado forming probability of it hailing is likely. The backdrop of the clouds is correct. But just like the sky and the water reflect off of each other, it would also reflect off of the hail. The hail very seldom reaches the ground because of the powerful winds and also because of the rise in temperature that happens briefly before the tornado forms. All of these components changes the color of the sky, just like the common knowledge of combining two colors; yellow and blue makes green. In this case, it’s different variations of colors. I am right and you are all wrong! Epic fail! If you have any questions, I am a member of MENSA, and my IQ is 187. And I am a Christian, so my knowledge is righteous. Amen!!!

    • Ashley says:

      Lost all perceived validity thanks to those last few comments.

      …Really?

    • haley says:

      wow, your a jack! im a christian, i didnt know that were to be so proud and so quick to prove others wrong?- or by what you think you know…. if im correct(let me know if im not, im sure you will)the bible speaks of humility???and i agree with the validation, i almost fell for it but your last few kinda bit me. ONE: extreemly unprofessional TWO: as a christian, you should be ashamed of yourself. to be a christian, you should have pride in being true, and being “Godly”. Jesus would not have made an ass out of himself to try to say basically the same thing to try to pprove a point.-which was???

    • Noah says:

      Lol, I think I’m going to start tacking that onto my comments at the end. Nice troll.

  2. I can’t say what causes it, but the green tinges in these clouds had me worried (needlessly) a few weeks ago:
    http://www.facebook.com/album.php?aid=59595&id=1575777222&l=6a0fdb6059

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