Fall Streak Hole Clouds: Fun Facts About These Rare Cloud Formations
The nature and science of punch hole clouds in the sky
A couple of years ago, in Mount Vernon, Washington, I looked up to see these weird cloud formations. I had to research what they were. It turns out they were fall streak hole clouds.
Sometimes known as hole punch clouds, they are a sight to see and quite rare, with their unique and mysterious presence. It was almost eery.
Formation and Characteristics of Fall Streak Holes
Fall streak holes are fascinating clouds that are round with a hole or gap in the middle and a cloud ring. A “streak,” or hole, appears as if part of the cloud was punched out.
Fall streak holes develop from temperature, humidity, and ice crystals. Supercooled water droplets in the cloud layer can freeze onto ice nuclei, generating ice crystals.
When these ice crystals expand, they fall through the cloud layer and evaporate, producing a hole.
Some are more oval-shaped than round. Wind patterns, atmospheric conditions, and other cloud forms affect the shape and size of fall streak holes.
Although circular fall streak holes are the most common variant, other variants exist. Ice crystals fall through a horizontally extended cloud layer, forming canal clouds, which are shaped like a canal or river-like stripe that appears in the sky.
The Science Behind Fall Streak Holes
Hole punch clouds begin with the weather circumstances that cause them. Supercooled water droplets in altocumulus or cirrocumulus clouds cause fall streak holes. The droplets stay liquid at below-freezing temperatures. I am still determining how that is possible.
An airplane traveling over the cloud layer upsets the balance of the supercooled droplets, which freeze onto ice nuclei and create ice crystals. These ice crystals form and fall through the cloud, creating a hole or streak.
Wind shear, which changes wind speed or direction with altitude, can also contribute to this. The horizontal spreading of ice crystals by wind shear can create canal clouds or streaks.
While streak hole formation parameters are unknown, scientists study them to learn more about cloud physics and atmospheric dynamics.
Conclusion
Fall streak holes or punch clouds in the sky are fascinating for weather enthusiasts, people who love nature, and curious people.
Thanks for reading. All rights reserved by Val Garner
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