Taking a piece of the sky: How hole-punch clouds form

You’re probably familiar with those fluffy cumulus clouds or a stormy cumulonimbus on a summer day, but have you ever heard of a fallstreak hole?

Also known as a hole-punch cloud, these large, circular gaps appear in cirrocumulus or altocumulus clouds.

Tiny water droplets that have yet to freeze make up high to mid-level clouds. These “supercooled” water droplets usually only freeze when brought into contact with ice crystals.

Planes passing through the cloud can help the water freeze. The air expands and cools as it moves around the wings or the propeller, quickly pushing the supercooled water to the point of freezing.

The ice crystals that form absorb the nearby water droplets and start to sink. Left behind is a hole in the clouds, which expands once more droplets freeze. 

If you have a picture of a hole-punch cloud share it with us.