Hole Punch, Fallstreak and Sundog

April 13, 2011

Photographer: Brian Ritzer
Summary Author: Brian Ritzer; Jim Foster

April 2011 Earth Science Picture of the Day Viewer's Choice

The photo above showing an extraordinary hole punch, fallstreak and sundog was captured over Chesapeake, Virginia on January 4, 2011. Hole punches occasionally result when jet aircraft pass through shallow, mid-level cloud decks. As the supercooled water droplets in the cloud layer are jostled by the transiting aircraft, they instantly freeze. Latent heat is then released, which warms the air and evaporates a portion of the cloud in near the transit. Note the swarm of ice crystals (fall streak) falling through the huge gap in this altocumulus cloud deck. Because the punch was within 22 degrees of the Sun (at far right), the pencil-shaped ice crystals formed a sundog or parhelion, nicely accenting the opening. Be careful to protect your eyes when looking toward the Sun.