Hole Punch Cloud in Altocumulus Cloud Deck
January 25, 2018
Shown above at bottom center is a hole punch cloud with a well-developed fallstreak as observed over the rooftop of my house in Dublin, Ohio. I was captivated by the altocumulus clouds that filled much of the sky this late December day and decided to make a panorama, not realizing right away that this hole punch cloud had formed. Mid-level cloud decks, composed of supercooled water droplets that freeze when jostled, are typically quite shallow and are easily disturbed when passed through by an airplane or jet. The latent heat released during this change of state, from a liquid to a solid (referred to as the heat of fusion), evaporates cloud droplets, forming a gaping hole in the clouds. Ice crystals falling through this hole, called fallstreaks, are evaporated by the drier and warmer air just beneath the cloud deck. Note the smaller hole punch at lower left. Photo taken with my Phone6 on December 21, 2017, at 02:14 p.m.