Why do clouds turn green before a tornado occurs? Are these green clouds directly linked to tornadoes forming? Lets find out…
Hidden inside visible sunlight is the rainbow of colors all mixed up. If an object reflects back, or scatters all that light, that object appears to us, white as well. If an object absorbs all the light, and scatters none back, it appears black to us. That’s the main reason why my black car gets hotter than the white car parked next to me.
If an object absorbs only some of the colors in the spectrum and scatters back others, it appears to our eye, the colors scattered back. So a red apple absorbs blues and greens and scatters back red. Bodies of clear water, absorb reds, and yellows first, and scatter back mostly blue.
Some of the biggest thunderstorms can generate areas of concentrated heavy rain and hail that look like waterfalls. Storm chasers call this the core. Sometimes storm clouds part giving you a glimpse into the core aloft.
If you’re underneath the storm base, around midday, the core is often blueish or a gorgeous turquoise. But in the late afternoon and evening when most storm activity occurs, angled golden and reddish sunset light might mix with the blue precipitation core and the net effect is a greenish color. Yellow and blue makes green!
The sky is blue because the gas molecules mostly nitrogen and oxygen scatter the blue wave lengths all over the place while the warmer wavelengths tend to pass through. That's why the sunset turns red. As the sun's altitude becomes lower, it shines through more and more atmosphere. All the blue is scattered first and it's mostly only the warmer visible wavelengths that reach our eye.
Another way a storm can add a yellowish filter to the blue core is by kicking up a lot of dust. The more powerful the storm, the more wind, and often, the more dust flying through the air. Looking through this yellowish air into the blue core can also give a net greenish effect to a viewer.
So, what does it mean when the clouds are green? The green color in storms doesn’t guarantee a tornado, but it usually means there’s a powerful thunderstorm with heavy rain and hail.
And powerful thunderstorms that produce tornadoes often produce heavy rain and hail. So, it wouldn't hurt to have a plan if you see a storm cloud turn green.
Why are Tornadoes green? Tornadoes come on all the shades of grey, sometimes almost bright white, and other times dark black. This is all relative to the viewer and the current lightning situation. If a tornado is well lit, it appears brighter, If it is silhouetted against a brighter sky, it appears dark. Sometimes setting sunlight can shine on a tornado giving it an orange or yellow tint. But tornadoes are generally not green. Sometimes the clouds behind a tornado are green.
All storm footage by Hank Schyma copyright 2018
To license green storm cloud footage, contact hankschyma@gmail.com