Cavum, or hole-punch clouds, are intriguing cloud formations caused by airplanes traveling through midlevel clouds, particularly during winter months. These formations, resembling neat circles or ellipses in the sky, occur when supercooled water droplets freeze into ice crystals, a reaction triggered by the cooling effect of airplanes’ wings. The December 2, 2024, image captured by the Operational Land Imager-2 on Landsat 9 over Wichita, Kansas, illustrates two such cavum formations, showcasing the visual spectacle they create with feathery, cascading trails known as virga.
Mixed-phase midlevel clouds, like altocumulus and altostratus, cover about 8 percent of the Earth’s sky and are often associated with this phenomenon, particularly near airports. Studies indicate that the atmospheric conditions for cavum formation occur approximately 3 to 5 percent of the time overall, but can increase to 10 to 15 percent in winter. Factors influencing their creation include the angle of the aircraft’s approach, cloud thickness, air temperature, and wind shear. With about 34 flights daily from Wichita Dwight D. Eisenhower National Airport, such formations may frequently be observed.
