Have you ever looked up at the sky and seen a big hole in the clouds? It looks like someone took a giant cookie cutter and punched it out! These holes are called cavum clouds. They are also sometimes called hole-punch clouds or fallstreak holes.
People have mistaken cavum clouds for flying saucers or other strange things. But scientists know they are caused by airplanes flying through clouds.
Cavum clouds are also commonly called hole-punch clouds because in certain weather conditions aircraft can punch through the clouds leaving a clear hole in the center.
The process happens in air below freezing with tiny drops of water that are still liquid. Droplets don’t freeze since the air is pure without dust for ice to form on. That’s until a plane flies through these clouds, cooling the air around it to the point water droplets can freeze and turn into ice crystals. The ice crystals then fall out of the sky, leaving a hole in the cloud.
Cavum clouds can be of different shapes and sizes. They can be small, round, or long and thin. They can also be called “canal clouds” because of their long shape when planes pass through the cloud layer at an oblique angle.
Cavum clouds are pretty distinctive to spot, and when they occasionally show up over Jacksonville — people are sure to take notice.