Cirrocumulus lacunosis Clouds

Cirrus lacunosis, photo by Craig Johnson at Cedar Falls, Iowa

This is not a common everyday run-of-the-mill cloud. On the other hand they appear often enough that you should be on the look-out for them. Look past the lower cumulus clouds and you will see cirrocumulus lacunosis. The definition from the World Meteorological Organization states, “Cloud patches, sheets or layers, usually rather thin, marked by more or less regularly distributed round holes, many of them with fringed edges. Cloud elements and clear spaces are often arranged in a manner suggesting a net or a honeycomb.”

This cloud type is most often found at the cirrus level but can also be seen as a type of altocumulus and rarely a stratocumulus. The lacunosis in this photo are at the cirrus level. They have irregular edges with holes in the middle. The lower clouds are cumulus. Lacunosis often have a honeycomb shape. This cloud type forms when a layer of cool air mixes with a higher warmer layer in the atmosphere. When at the cirrus level the layers of air are only relatively warm and cold. Temperatures, even in the summer are below freezing.