Noon on January 15, 2024 provided an extraordinary spectacle in the sky of Arabba and the Dolomites: an iridescent cloud painted the panorama of the Porta Vescovo ridges with vibrant colors, following a Foehn wind of extraordinary intensity. This spectacle, far from being a coincidence, is the result of a fascinating natural phenomenon, capable of touching emotional chords without raising concerns.
But what exactly is this "rainbow cloud" and why did it manifest itself in such an extraordinary way?
Iridescent clouds, a rare but amazing phenomenon, are formed by tall, thin clouds consisting of tiny water droplets or ice crystals. These particles act like prisms, breaking down sunlight into its various colors, giving a spectacle reminiscent of a rainbow. But it is not only the rarity of the phenomenon that makes it unique. The scientific explanation points out that weather conditions on the Italian Alpine slope have created a perfect environment for the formation of thin clouds at high altitudes, which are ideal for iridescence.
The phenomenon of iridescent clouds is driven by an intricate ballet of sunlight, 'shear' clouds and special weather conditions. The clouds, composed of water droplets or ice crystals, deflect light rays from the sun, creating a prismatic effect that gives life to the colours of the rainbow. But not all clouds can give this spectacle: we need thin, semi-transparent clouds, uniform in particle size. The incredible phenome in mid-January was favoured by weather conditions, fuelled by an intense Foehn wind that affected the Dolomites. This warm, dry wind, generated by the rapid passing of an air current over the Alps, helped to form thin clouds at high altitudes, becoming the prelude to a celestial spectacle that enchanted everyone who looked up to the sky, skiers and non-skiers alike.
In conclusion, the phenomenon of iridescent clouds, fascinating and spectacular, not only enriches our visual baggage but also reminds us of the beauty and complexity of nature around us. An unexpected but absolutely welcome gift, which transformed the sky of the North East Alps, in Arabba, the centre of Dolomiti SuperSki, into an emotional painting to be admired and remembered.
Photo Credits: Graziella Crepaz