Why are the clouds before a tornado green?

Answer 1

While, dangerous thunderstorms that drop hail and spin up tornadoes seem to be routinely observed as turning green ("going green" in the movie Twister), scientists are trying to find out what exactly is going on.

They have confirmed that some thunderstorms do turn green, and have various theories about why.

One possibility is that thick, thunderstorm clouds, with their water vapor, rain and hail, scatter sunlight in such a way as to give the clouds a blue hue.

When the sun is low in the sky, such as before sunset when most severe storms occur, the reddening light of the sun when shining through Earth's atmosphere makes the bluish cloud tint turn green.

Or, maybe storm clouds act as a kind of canvas upon which low sunlight, scattered by particles in the air, paints a greenish color.

Both of these could be correct, and they may play in concert with each other to create the observed green tint.

In the spring of 1995, a University of Oklahoma graduate student used a special device called a spectrophotometer to measure the wavelength of light emitted from thunderstorm clouds during Project VORTEX, a major study of tornadoes. (Related: U. of Okla.: Green thunderstorm presentation).

His research confirmed green, greenish-yellow, and greenish-blue colors of the clouds, while ruling out lush farmland as the source of the green color.

But the researcher concluded that the actual green color observed may be different for different people. In other words, what may look strikingly green to one person, might be more greenish-blue or greenish-yellow to someone else. Maybe not even green at all.

All that's known for sure is that green thunderstorms do exist. It's not known whether all green thunderstorms are severe, nor whether all severe thunderstorms turn green.

The best advice: don't wait to see green clouds before seeking shelter from severe thunderstorms.

Answer 2

Green Clouds Tornado

Answer 3

I just read about this last week in a book. A study was done back in 1995 using a spectrometer to measure the wavelengths of the color spectrum to show that there were indeed more green wavelenths in the sky under some thunderstorms.
Three factors affect the amount of light passing through a cloud, cloud thickness, droplet size, and droplet density within the cloud. So some thunderstorms tend to have a grayish-blue hue because they are dense with a lot of small water droplets. The greenish clouds came from clouds with a lot of larger droplets. Clouds with hail also tend to selectively scatter to that they appear green. A high hail content in clouds also occurs when tornadoes occur. But not all tornadic/hail producing/severe thunderstorms appear green. This is just to prove that in the cases where some do look green, there actually is an increased amount of green wavelengths in that cloud.

Answer 4

While, dangerous thunderstorms that drop hail and spin up tornadoes seem to be routinely observed as turning green ("going green" in the movie Twister), scientists are trying to find out what exactly is going on.

They have confirmed that some thunderstorms do turn green, and have various theories about why.

One possibility is that thick, thunderstorm clouds, with their water vapor, rain and hail, scatter sunlight in such a way as to give the clouds a blue hue.

When the sun is low in the sky, such as before sunset when most severe storms occur, the reddening light of the sun when shining through Earth's atmosphere makes the bluish cloud tint turn green.

Or, maybe storm clouds act as a kind of canvas upon which low sunlight, scattered by particles in the air, paints a greenish color.

Answer 5

There is no sickening color, there might be a green tint to the sky caused by the refraction of light off of hail which is common in the the large storms that can spawn tornadoes. Green is not always an indication of a tornado, it just means that there is probably some large hail in the storm and you should seek shelter and protect the windshield on your car.

Answer 6

No one knows exactly, but here's one idea...The colors that comprise sunlight get absorbed, reflected and scattered as they encounter the particles in our atmosphere (like Water, Nitrogen, Oxygen, Dust, etc...)

Exactly why the green hue appears is not exactly known, but the tremendous amount of water vapor, ice crystals, and rain in the air during strong T-storms may be the culprit. Perhaps sunlight that does encounter all those water molecules, gets selectively scattered, meaning mainly the green part of the sunlight is scattered. This optical phenomena is the reason behind our sky being blue and sunsets being red. Depending on the angle of the incoming sunlight, it will be selectively scattered and thus only certain colors in the color spectrum are scattered. Remember that this is just one theory, and no definitive explanation has been proven.

Answer 7

They aren't really. On everyday in Oklahoma that we have tornadoes the clouds are gray, white, red, or black. That includes May 3, 1999.

Answer 8

I don't know, but I seen the sky bright orange before and after a tornado one time...it was a lil freaky!

Answer 9

A greenish tint to a cloud base according to popular belief indicates hail.

Answer 10

Its a simple matter of filtered sunlight.... light is filtered through wather droplets, water vapor, dust, and lord knows what else, and the green band of the spectrum is often the only light that makes it through... hence, they appear green.