photo #6832433

This Cirrus cloud hides a history in its fernlike forms. It was spotted over Cornwall-on-Hudson, New York, US by George Preoteasa (Member 41,445). At this stage in its development, the cloud would best be classified as a Cirrus fibratus because it’s a high cloud consisting of streaks of falling ice crystals, some of which are arranged into fine parallel filaments, mostly visible in the bottom right of the image. But these fibratus filaments seem like minor features compared to the overall appearance of the cloud as a fan of broad fronds, each with parallel ribs down its length. It is a pattern not normally seen in Cirrus clouds.And that’s because the cloud likely started out as a different formation: still a high cloud, but one with a more solid appearance that was arranged into parallel ribs and bands due to the shearing effect of the high-altitude winds. This formation would have been classified as Cirrocumulus lenticularis undulatus. And if its supercooled water droplets all froze into ice crystals, the Cirrocumulus (the most fleeting and short-lived of the ten main cloud types) would have transformed into Cirrus with a distinctive fractal pattern of filigrees and fronds.