This Thursday, a young Toulousain noticed in the sky a funny cloud in the colors of the rainbow. It is an iridescent cloud, a phenomenon usually observed in the mountains or from the plane.
It’s not magic but almost. This Thursday, shortly after 1 p.m., Willo, a 19-year-old former student from Toulouse, takes a selfie in the street while he goes shopping. In the photo taken from the paved Côte district in Toulouse, he notices a strange cloud behind his head. He zooms in: a cloud in the colors of the rainbow like he has never seen. Immediately, he types on the Internet: “rainbow cloud” and discovers that it is an iridescent cloud. Willo can’t believe it: “It’s incredible”.
“It is a phenomenon of iridescence: when the sunlight passes through fairly thin clouds of ice, we can see colors appear like those of a rainbow,” explains Pascal Boureau, forecaster at Météo -France in Toulouse. “Since the beginning of the afternoon, the clouds have been located at high altitude, approximately 7000 meters above the sky of the Pink City. At this altitude, it is approximately -50 ° C and the clouds are charged in ice crystals “, specifies the expert. This afternoon in the Toulouse sky, all the lights were green to see this phenomenon appear: “The atmosphere has been quite dry since the fog lifted, this is one of the essential conditions to be able to see a iridescent cloud “. The edges of the cloud then take on a generally red, green or pink coloring.
However, this phenomenon is not as rare as one might think. “I saw more iridescent clouds than shooting stars. The specificity is that the phenomenon is visible only on a small surface which often escapes the eye”, adds the specialist. But in the photo taken by Willo, the colors blue, green, yellow and red have spread enough over the cloud and are clearly visible. You can observe these iridescent clouds in the mountains or from the plane. But it is better to be at the right time in the right place because the rainbow palette that the cloud takes does not last long: “Only 2 to 3 minutes generally, sometimes up to thirty minutes but it is rare”, explains Pascal Executioner.