Gothamist sensed something was wrong when the studio at work went dark all of a sudden yesterday afternoon. A glance out the window showed a mass of thick, dark, low lying clouds approaching. What was curious, and quite impressive, was the yellowish green glow that an area of the clouds had. It was very cool, but also extremely eerie. An email quickly went off to fellow Gothamist weather geek and resident Meteorologist, Joe who was also slightly north and viewing the same approaching storm.

What caused the yellowish green, smoking science experiment in the sky? Ever see Twister? Notably severe thunderstorms that carry the potential for hail and tornadoes frequently take on a greenish or similar tint. Currently there is no definitive explanation for it, but there are various theories. One of them suggests that the ice and hail in the clouds causes preferential scattering of certain wavelengths of light.

In 1995, a University of OK grad student was doing a study on tornadoes and used a spectrophotometer (which measures the wavelength of light of course), to study the light emitted from storm clouds. The study confirmed the presence of greenish light ruling out that it was caused by reflecting light from surrounding greenery or farmland. It went on to say that the liquid water content of storms can vary the color from a bluish green caused by smaller drops, to a yellowish green cased by larger drops and that large hail cannot create the light on it's own.

Still, while it's been proven that the light emitted from the storm is in fact greenish, the explanation is still theory. Maybe the hail forming in the clouds is a form of kryptonite. whatever the reason, Gothamist was happy to have his trusty digital camera yesterday.

Luckily there were no reports of hail and as Joe pointed out, there was no wind shear for tornado development. If you find yourself stuck in a storm that is "going green", you should plan to get somewhere safe soon, and know the potential for a severe storm that could potentially produce hail and or tornadic activity is high.