Hole Punch Cloud Observed Over Los Angeles, California
March 08, 2017
The photo above showing a blimp-shaped hole punch cloud was taken near my home in Los Angeles, California. A characteristic of nearly all hole punches is that they're typically surrounded by mid-level clouds, which is a clue to their formation. The supercooled water droplets that compose such clouds freeze when disturbed by the passage of an airplane or jet, and the resulting ice particles then begin to fall toward the ground as fallstreak streamers -- the brighter white area within the confines of the hole punch. As the droplets freeze heat is released (heat of fusion). This causes nearby droplets to evaporate, forming a large hole in the cloud deck. Photo taken out of the car I was riding in on January 12, 2017.