Hole Punch Clouds
This photo taken in Ashland, Kentucky USA on December 2, 2006. An elongated hole-punch in the cloud layer, across much of the sky.
See my photo and other “hole-punch clouds” here:Project Atmosphere Australia Online
Hole Punch Clouds are unusual cloud formations, which many call ‘hole punch’ clouds or fall streak holes – essentially, ‘glaciating supercooled cloud’ – ice crystals falling through a supercooled layer of cloud. This is an extremely unusual event to witness and some are quite spectacular.
ACCORDING TO NASA: Very unusual to see, hole-punch clouds like this are still the topic of meteorological speculation.
A leading hypothesis holds that the hole-punch cloud is caused by falling ice-crystals. The ice-crystals could originate in a higher cloud or be facilitated by a passing airplane exhaust. If the air has just the right temperature and moisture content, the falling crystals will absorb water from the air and grow.
For this to happen, the water must be so cold that all it needs is a surface to freeze on. The moisture lost from the air increases the evaporation rate from the cloud water droplets so they dissipate to form the hole. The now heavier ice crystals continue to fall and form the more tenuous wispy cloud-like virga seen inside and just below the hole. Water and ice from the virga evaporates before they reach the ground.
See this photo and other “hole-punch clouds” here:Project Atmosphere Australia Online
ALSO GO TO NASA’S ASTRONOMY ‘PICTURE OF THE DAY’ TO LEARN MORE ABOUT HOLE-PUNCH CLOUDS: GO HERE:NASA’s PIC of THE DAY