Carole Marshall wrote about seeing green clouds at the Broward Shell Show
in Florida. You didn't mention the time of day, Carole, so I don't know
whether the green clouds were part of a sunset. Greenish tints are common
in sunsets, occurring for the obvious reason: refraction of sunlight in the
atmosphere. This is not the same as the green flash, which is just a tiny
spark of the sun itself.
 
On San Salvador in the Bahamas, I saw clouds whose bases were tinted a
delicate green while the sun was high in the sky. I asked other people if
they saw the same thing and they confirmed that the clouds were indeed
slightly greenish. The clouds were green because they reflected the
beautiful aqua (light, clear blue-green) of the shallows around the island.
I took several photos and confidently scheduled a talk on "San Salvador:
Island of Green Clouds" for the Alabama Geological Society (whose rule is
that slide shows can be on any subject as long as it is not on Alabama or
on geology). The show was mostly on the culture and natural history of the
island, and was well received, but the film did NOT record the green tint
very well and I have been accused of hallucination ever since!
 
So, Carole, do be careful who you tell about these green clouds. Get some
photos and LOOK at them first!
 
Andrew K. Rindsberg
Geological Survey of Alabama
Tuscaloosa, Alabama, USA