NORFOLK, Va. — Have you ever been in a thunderstorm or noticed one coming towards you and wondered why the sky looked a little green?
If not, that's okay because it doesn't happen very often. But sometimes the sky can take on a green hue when just the right conditions are happening within a storm. It involves the scattering of light!
Thunderstorms are typically associated with cumulonimbus clouds towering into the sky that can reach heights up to 60,000 ft and contain a significant amount of water and ice. When sunlight passes through these dense clouds, the shorter blue and violet wavelengths are scattered out, leaving the longer wavelengths, such as red and yellow, to pass through.
This process is similar to why the sky appears blue on a clear day, due to the scattering of shorter wavelengths by the atmosphere.
The green color specifically arises when the sunlight interacts with the water droplets and ice particles within the storm clouds. The reddish-yellow light passing through the storm clouds can be scattered by the water and ice particles in a way that it creates a greenish tint.
This effect is most pronounced when the storm is approaching sunset, as the angle of the sun can enhance the scattering effect.
The green color can also be a warning sign of severe weather, specifically the potential for hail. That's because hailstones reflect and refract light in a way that can contribute to the greenish coloration of the clouds.
