photo #6349001

Near Madison, Ohio, US, J Pogalies (Member 62,612) spotted a stormy sky with a distinct shade of green when a huge Cumulonimbus spread its skirt-like arcus cloud feature out across Lake Erie. J described the dramatic cloud as a ‘drama queen’. A green tinge like this does sometimes appear in powerful storm clouds. Some say the hue indicates that a storm contains hail or is likely to produce a tornado, but there is no solid evidence for this. The truth is, no one knows for sure why powerful storms sometimes look green. One theory is that it’s due to the raindrops and ice crystals in the storm’s precipitation scattering the sunlight that shines through it.In normal daylight, the smaller particles in the shower might be expected to have a bluish tint because small particles scatter more of the short, blue-looking, wavelengths of visible light. Even if the angles are right for blue light to be scattered in your direction in this way, the cloud would be expected to appear blue, not green. According to the theory, a greener hue happens when the light shining through the shower comes from a low Sun. This light would already have had its short, blue-looking, wavelengths scattered away on its journey through the low atmosphere. A golden light would be reaching the far side of the shower to shine through. With its shorter, blue-looking, wavelengths out of the picture, only the next hue in the spectrum, a greener-looking light, would result from the scattering influence of the shower. The theory can’t explain any association with hailstones, which are too large to scatter sunlight in this way, let alone tornadoes. This drama queen keeps her secrets hidden.