observed in Germany. Image uploaded to the web – o2

A photo taken in the city of Mannheim, West Germany, appeared on the Internet. The picture shows a cloudy sky in one great detail. A huge circular hole formed in the middle of the clouds just above the church tower. It is not an isolated phenomenon. He appears quite often and got his name.

Cavum means cloud in the cloud. Sometimes it is colloquially called a puncher. This is the shape of a round or oval hole in the center of the clouds. How does such a phenomenon arise?

In order for such a phenomenon to appear, Altocumulus, Altocumulus or Altocumulus must be strongly cooled. Its temperature should be as low as minus 30 degrees. In the atmosphere, there should be neither sudden air movements nor condensation nuclei on which droplets can settle and freeze. When such conditions are interrupted, for example, by an airplane, then caving occurs.

When this “calm” in the atmosphere is broken, the supercooled water droplets instantly freeze to form ice crystals. It begins to fall under the influence of weight, but does not reach the surface of the earth because it evaporates at high temperatures. Then a hole forms in the clouds. In it, the Cirrus cloud is formed. Under favorable conditions, clouds may become iridescent at the same time.

Cavum is just a short name. It changes depending on the clouds in which the clearance is created. Sometimes, it may even appear altocumulus perlucidus translucidus cavum.