Hole-Punch Cloud

Clouds : classification
Genera Cirrus Ci Cirrocumulus Cc Cirrostratus Cs Altocumulus Ac Altostratus As Stratocumulus Sc Stratus St. Cumulus Cu Nimbostratus Ns Cumulonimbus Cb	species calvus cal capillatus cap castellanus cas congestus con fibratus fib floccus flo fractus fra humilis hum lenticularis len mediocris med nebulosus neb spissatus spi stratiformis st uncinus unc volutus vol	Subspecies duplicatus you intortus in lacunosus la opacus op perlucidus pe radiatus ra translucidus tr undulatus un vertebratus ve Special forms arcus arc asperitas asp cauda cau cavum cav fluctus flu flumen flm incus inc mamma mam murus mur pannus pan pileus pil praecipitatio pra tuba tub velum vel virga vir

A hole-punch cloud (from English hole punch = hole , also punch-hole cloud and fall streak hole ) is a relatively seldom observed weather phenomenon and describes a compact cloud with bizarre tips that stand out from them with a clear circular to oval free space surrounding clouds - mostly altocumulus , more rarely cirrocumulus or stratocumulus .

Hole-Punch Cloud over East Westphalia

Hole-Punch Clouds over Texas (see also image description page in English)

Hole-Punch Cloud at a very late stage

Theories on the origin of the cloud holes

The exact cause that leads to the formation of the cloud has not yet been researched. It is believed that it is caused by rapidly falling ice crystals . Aircraft as the cause are not excluded.

The falling ice crystals either come from a higher cloud or they were produced by the engines of an airplane flying overhead. The falling of the ice crystals makes it possible to absorb water because the humidity binds to the ice. Snowfall occurs in the center of the cloud when it is formed , the cloud grows and the cloud-free distance to the old clouds increases. As they sink, the ice crystals grow into deeper layers of the air and thereby remove moisture from the environment. In this way, where this phenomenon occurs, a large gap is created in the cloud layer. Why the formation is locally limited has not yet been scientifically researched.

The ice crystals become increasingly heavier due to the additional water absorption and fall faster towards the earth's surface . The process takes long enough, because according to many ice crystals fall much or surrounding humidity is present that forms at the bottom of hole-punch cloud from the fallstripes a funnel-like structure, but not with Tornado clouds should be confused. However, the snow does not reach the earth because it is heated in deeper layers of the air and melts or sublimates directly .

Web links

Commons : Hole-Punch Clouds  - Collection of Images

• Hole-Punch Cloud, filmed in Romania - Report from October 26th, 2009 on the Daily Telegraph website
• Punch-Hole / Fallstreak Hole cloud, photographed in the Allermarsch west, October 2009
• Hole Punch Clouds: OWL is amazed by the perforated cloud cover Report from October 6, 2019 MT-Online

Individual evidence

1. ^ A Hole Punch-Cloud Over Alabama - Astronomy Picture of the Day of January 12, 2004 (English).
2. ↑ SF-METEO: Hole-Punch Cloud
3. ↑ ZDF Wetter: Wolkenlöcher im Vogtland - Hole-Punch Clouds ( Memento from August 15, 2009 in the Internet Archive )