AUSTIN, Texas (KXAN) – Some people living around Austin, Texas, were curious to know what caused the mysterious-looking hole in the sky Tuesday afternoon.
What is it?
A “hole punch cloud” (or “fallstreak”) is circular gaps in altocumulus or cirrocumulus clouds. These mid- to high-level clouds are composed of “supercooled” water droplets, or liquid droplets much colder than freezing but that have yet to actually freeze. What’s missing? Ice crystals.
Planes moving through these clouds leave behind tiny ice crystals. Once these supercooled droplets have something to “cling” to, the droplets freeze, grow and fall, leaving behind a hole in the cloud layer. The hole continues to grow as neighboring droplets begin to freeze.
It’s a natural, harmless and normal weather phenomena but still a treat to see in person.