Hole punch clouds make a rare, wonderful spectacle in the sky for everyone to observe. What a beautiful gift of the nature - which could also send rain or snow to the earth.
This photo taken in October 2002 from the Clifton Commons shopping mall in Clifton, NJ. Thanks to Steven Krisocki for this one! http://http//www.schools.ash.org.au/paa2/mediagallery/gallimage.asp?pid=596&gallid=5&gallcatid=15&fileid=32&uid=
A hole punch cloud is a giant circular gap that appears in otherwise continuous clouds, caused by a passing airplane, and potentially responsible for increased precipitation around airports.
It appears to be a rather widespread effect for aircraft to inadvertently cause some measureable amount of rain or snow as they fly through certain clouds, said lead author Andrew Heymsfield of the National Center for Atmospheric Research, Boulder, Co., NASA reported. This is not necessarily enough precipitation to affect global climate, but it is likely to be noticeable around major airports in the midlatitudes.
When a layer of supercooled liquid water clouds is stretching across the sky in subfreezing temperatures, an airliner gaining altitude punches through the cloud layer, and leaves behind a void as if by a circular cookie-cutter, explained Patrick Lynch in NASA's Earth Science News Team.
In some cases, the shape left behind is more ragged, or even more rectangular or canal-like.
The ice particles grow at the expense of the supercooled water droplets and fall out of the cloud as snow. If the cloud layer is thin or if the water is not replenished the snow leaves a hole in the cloud, stated Lynch.
Fantastic - this would have been nice to watch. Note the virga seems confused here. Subimitted by Randy & Theresa of Simpsonville, SC in the USA. http://www.schools.ash.org.au/paa2/mediagallery/gallimage.asp?pid=596&gallid=5&gallcatid=15&fileid=393&uid=
According to Project Atmosphere Australia Online,
The growing ice crystals fall out as snow, and the fallstreaks of this snow are clearly visible in the pictures. So the result is a hole in the cloud, and snowstreaks stretching down. Now this snow never reaches the ground because it sublimates (evaporates) in the drier air below. The snowstreaks stretching furthest down (ie the 'twister' as somebody suggested) indicate the impact point of the aircraft, the point where the freezing first started.
Observation of the hole punch clouds was first reported in the 1940s, often leading to false reports of UFOs or rocket launches.
Here are some photos of hole punch clouds:
A hole punch cloud observed on August 17, 2008 near Linz, Austria. Credit: H. Raab/NASA
This image, taken by the Landsat-5 satellite on December 11, 2009, shows the unique conditions in which holes in clouds form. Credit: Robert Simmon/NASA Earth Observatory
A hole punch cloud visible over Omarama, New Zealand in May 2006. Credit: Dollsworth/NASA