



Photographer: Alan Sentman

Summary Author: Alan Sentman

When running a few weeks back near Christiansburg, Virginia, I came over a hillcrest and found I was staring straight at a hole punch cloud. Although I had known about these oddities for some time I hadn't seen one before and was so surprised to see this one that I stopped dead in my tracks. Hole punch clouds form when supercooled cloud droplets are disturbed by the passage of an aircraft. The droplets freeze and fall down as fallstreak streamers, visible here below the cloud deck. This releases heat (heat of fusion), causing surrounding water droplets to evaporate, leaving a gaping hole in the clouds. Photo taken on March 18, 2015.