photo #4257858

This is a textbook example of the uncommon cloud variety called lacunosus (from the Latin for ‘having holes’) appearing in Cirrocumulus clouds over Grapevine, Texas, US. Spotted by Yves Leenders (Cloud Appreciation Society Member 37,343), this short-lived variety is characterised by evenly-spaced circular gaps that are surrounded by fringes of cloud to resemble lacework. The holes are formed as cooler air above sinks in pockets, with the cloud fringes forming where warmer air rises from beneath to replace it. Not only is this lacunosus pattern a fleeting variety, but Cirrocumulus, the high layer of cloudlets in which it has appeared, is the most short-lived of all the ten main cloud types. Cirrocumulus is a cloud in transition on account of being made of supercooled water droplets that soon freeze in the high altitudes, when the cloud develops into the other high clouds, Cirrus or Cirrostratus. Which is all to say, best to enjoy this fine lacework of the sky before it unravels