Mind-Blowing Cloud Formations You Probably Haven't Seen Before

Aircraft, which often have a large reduction in pressure behind the wing- or propeller-tips, punching through this cloud layer can cause air to expand and cool very quickly as it passes over the aircraft wings or propeller. This change in temperature can be enough to encourage the supercooled droplets to freeze and can produce a ribbon of ice crystals trailing in the aircraft's wake. The ice crystals then fall from the cloud layer. When ice crystals do form, a domino effect is set off due to the Bergeron process, causing the water droplets around the crystals to evaporate: this leaves a large, often circular or elliptical, hole in the cloud with streaks of ice crystals below the hole.