Sometimes clouds take on amazing shapes that don't even look like a real cloud! I'm not talking about clouds that look like rabbits, but something more amazing like this fallstreak hole!
I'm talking about a formation of clouds that look like superman punched a hole in the sky. These fallstreak holes (or hole punch clouds) are quite rare, but they're also a bit jarring to see. The first two images show the fallstreak hole found in the sky over Victoria, Australia recently. This one had a rainbow in it! You can see two other hole punch clouds in the 3 and 4 images that don't have a rainbow, and they just don't look nearly as amazing.
How does a fallstreak hole form? When mid and high level clouds (which are often composed of tiny water droplets) and sometimes these tiny water droplets have yet to freeze. These "supercooled" water droplets need a "reason" to freeze, which usually comes in the form of ice crystals. Sometimes, planes passing through the cloud layer can bring these ice crystals. Once the ice crystals are there, the water droplets quickly freeze and start to fall. A hole is left behind, which will start to expand outward as neighboring droplets start to freeze. Viola!