A "sky hole" is a common term for a hole punch cloud, a fascinating atmospheric phenomenon that appears as a circular or oval-shaped opening in a cloud layer.
How do Sky Holes Form?
Sky holes form when ice crystals in high-altitude clouds, like cirrocumulus or altocumulus, sublimate, meaning they transition directly from solid ice to water vapor. This sublimation process can be triggered by several factors:
- Aircraft Contrails: Passing aircraft can create a trail of ice crystals that can seed the formation of a sky hole.
- Temperature Inversions: When a layer of warm air sits above a layer of cold air, the temperature difference can cause sublimation and create a hole in the cloud layer.
- Strong Winds: Strong winds can shear off portions of clouds, leaving behind a hole.
What Happens in a Sky Hole?
Once the hole forms, the surrounding cloud layer can begin to fall through the opening. This creates a downward draft of air, which can lead to turbulence for aircraft flying through the hole.
Examples of Sky Holes:
- Fallkirk, Scotland, 2017: A dramatic sky hole formed over Fallkirk, Scotland, creating a stunning visual spectacle.
- New Zealand, 2019: A sky hole formed over New Zealand, prompting speculation about UFO sightings.
Understanding Sky Holes:
Sky holes are a natural phenomenon that are often mistaken for UFO sightings. However, they are simply a result of atmospheric processes and do not pose any danger to humans or aircraft.
