Weird cloud over Moscow

My name is URL

I don't know if this has been posted already, just saw it on another site.

https://www.youtube.com/watch?v=sHOPxVM6oIw

has anyone any idea what causes this?

madziuda

http://en.wikipedia.org/wiki/Hole_punch_cloud

"A fallstreak hole (also: hole punch cloud and punch hole cloud) is a large circular gap that can appear in cirrocumulus or altocumulus clouds. Such holes are formed when the water temperature in the clouds is below freezing but the water has not frozen yet due to the lack of ice nucleation particles. When a portion of the water does start to freeze it will set off a domino effect, due to the Bergeron process, causing the water vapor around it to freeze and fall to the earth as well. This leaves a large, often circular, hole in the cloud"

http://www.meteorologynews.com/2009/10/12/hole-punch-cloud-not-ufo-spotted-over-moscow/

My name is URL

madziuda wrote: »

http://en.wikipedia.org/wiki/Hole_punch_cloud

"A fallstreak hole (also: hole punch cloud and punch hole cloud) is a large circular gap that can appear in cirrocumulus or altocumulus clouds. Such holes are formed when the water temperature in the clouds is below freezing but the water has not frozen yet due to the lack of ice nucleation particles. When a portion of the water does start to freeze it will set off a domino effect, due to the Bergeron process, causing the water vapor around it to freeze and fall to the earth as well. This leaves a large, often circular, hole in the cloud"

http://www.meteorologynews.com/2009/10/12/hole-punch-cloud-not-ufo-spotted-over-moscow/

Thanks!

I never heard of that type before.. pretty stunning looking

Deep Easterly

Wow, impressive cloudscape! I wonder would conditions at surface level have had any effect on this? like an industrial heat source or lake or something?