— from Gwyneth Burrill —
Fallstreak Hole and Sun Dog. Photo: Gwyneth Burrill
There was indeed a large “sun dog” to the left of this hole. It was a special moment to observe this!
Holes in clouds, most commonly called either hole punch clouds or Fallstreak holes, and also known as a hole punch cloud, punch hole cloud, skypunch, canal cloud or cloud hole, is a large circular or elliptical gap that can appear in cirrocumulus or altocumulus clouds.
These atmospheric phenomena are believed to be caused by the combined action of both mother nature and man.
For the Fallstreak hole to begin, cirrocumulus or altocumulus must contain super-cooled water which cannot freeze without a tiny particle to first cling to. Scientific opinion as to what finally causes the ice to form and begin to crystallize in the atmosphere has only solidified in recent years as meteorologists have become more certain that airplanes flying through the clouds start the process.
Air passing along propeller blades or wings expands and cools rapidly. The ice crystals begin to form and after the plane is long gone, the crystals can still be seen where they’ve dropped down below the cloud.
What’s left above the drifting ice particles is a round hole in the cloud that can sometimes be spectacularly large.
And if the sun catches the particles at just the right angle, another phenomenon called a sun dog can form as a bright patch of colored light hovering in.
Wow, Gwyneth, that’s amazing info. I remember in my younger days while accumulating hours for my ticket, we would sometimes be bad and punch a cloud or two when no one was looking. Now I know what I may have left behind! Cool!