Do you see the green, swirling storm clouds above you? Run! This means that the storm is particularly strong and dangerous, and perhaps a tornado is approaching.
Green clouds have long been considered a signal for the coming tornado or hail storm on the Tornado Alley – a huge area of the US that runs through northern Texas, Oklahoma, Kansas, Nebraska and beyond.
Folk wisdom says that the green color of the clouds is explained by frogs and grasshoppers that suck the tornado into the sky. In fact, the situation is somewhat different.
So, why are the clouds green? Storm hunter and blogger Pecos Hank explains that the point is how objects absorb and reflect sunlight.
Strongest thunderstorms can produce concentrated heavy rains and hail, which look like waterfalls. Storm hunters call this the core. Sometimes storm clouds give an opportunity to look at the core in flight. If you are under the base of a storm, at about noon the core is often bluish or turquoise. But towards evening and late at night, when the main storm activity is in progress, the golden and reddish sunset light can be mixed with the blue sedimentary core, and the result is a greenish light.
Green clouds are a reliable sign of a strong thunderstorm. Such clouds are often high, and high clouds are an important ingredient for potential hail storms and tornadoes. So, although the green clouds do not mean that the tornado is approaching, they say that a tornado can approach. Therefore, if you want to avoid heavy rain, strong wind and lightning, green skies are a sign that you should get ready and leave a dangerous place.