Punch hole clouds

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http://spaceweather.com/

TRIPLE PUNCH HOLE CLOUDS: "I've lived by the sea for many years, but never seen anything like this," reports Wesley Tyler of Myrtle Beach, South Carolina. "On Friday, Jan. 7th, there were three punch hole clouds in the same place." He grabbed his camera and recorded the phenomenon:

Considered a mystery for many years, punch hole clouds appear on rare occasions all over the world, sometimes attracting widespread attention, e.g., the famousMoscow UFO cloud of 2009. Recently meteorologists have penetrated the mystery: punch holes form when airplanes fly through thin layers of high altitude clouds. If water droplets in the cloud are supercooled (below freezing but still liquid), they can suddenly turn to snow when shocked by the passage of the plane. This mini-snowstorm occurs over a circular area much wider than the airplane itself.

Not all flights through banks of clouds will produce snow. According to Wired Magazine, only about 7.8 percent of the Earth’s surface is covered with clouds at the right elevation for supercooled droplets to form. Because jet aircraft don’t generally cruise at those altitudes, they may only form hole-punch clouds when they take off or land.

The apparition of three rare cloud-holes in one small area suggests a busy airspace around Myrtle Beach. Indeed, the Myrtle Beach International Airport is just miles from where the photo was taken. Or maybe punch hole clouds are a bit of a mystery after all.

[spiffybeth]

here's one i took of a hole punch cloud in MA

[bowtie`]

Cool image spiffybeth.

[bowtie`]

In 2004 I was able to image a jetliner flying through a thin cirrus layer probably between 30,000 and 40,000 feet. Did not produce a hole puch but it did produce a rolling *artificial* sundog. The cool thing was that the whole wing was producing a contrail, not just the engines.

I took this image and messed with the black and white points, which kind of turned it into a fake nightshot, but the purpose was to illustrate the prismatic effect of the whole wing lining up the orientation of the ice crystals and making the *sun-dog*.

For comparison, here is a *normal* contrail shot.

[dendrite]

I don't think you necessarily need a plane to witness them. I would think any fallstreak falling into an altocumulus layer like that could cause it.