A “holey” cloud appeared in the sky over the US state of Missouri yesterday. The image, captured by viewers of local TV station KY3 News, was shared by the city of Springfield's National Weather Service office.
The @KY3StormTeam sent us some photos that a few viewers sent in yesterday:
This is a “cloud of holes”. These can be caused by aircraft flying through a cloud, causing the supercooled water droplets in the cloud to suddenly evaporate or freeze and begin to fall. (1/2) pic.twitter.com/zji81IWsUH
NWS Springfield (@NWSSpringfield) December 20, 2023
But which cloud was that? Therefore, in English it is called “Hole Punch Cloud”, or in a loose translation a holey or perforated cloud. Perforated clouds form when part of the cloud layer freezes into ice crystals and falls out, creating a hole in the cloud layer.
This process is triggered by the presence of supercooled water droplets in the cloud. Supercooled water is water that remains in a liquid state even when it is below freezing.
When a plane passes through the cloud layer, the disruption it causes can cause some supercooled water droplets to freeze. These frozen droplets then fall out of the cloud, leaving a hole behind. The surrounding droplets begin to evaporate, creating a circular or elliptical gap in the cloud layer.
Perforated clouds usually have a welldefined circular or oval shape. They can be quite large and are often visible from the ground. Whenever they are created, they attract attention and the images end up on social networks dedicated to meteorology.
These hole clouds are often associated with certain meteorological conditions, including medium to high altitude clouds such as altocumulus or cirrocumulus. The presence of supercooled water droplets and appropriate temperatures are crucial for cloud formation.
Although uncommon, they are not rare and have been documented several times in the United States, where the climate is the coldest and air travel is the busiest in the world. Nevertheless, they can be observed in different parts of the world, provided the right atmospheric conditions are present.
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