From NASA’s Terra satellite, an image of fallstreak holes in clouds over the southern United States

© NAS

High above the clouds. What happened to these clouds?

Today is World Meteorology Day, so we’re high up in the atmosphere, above the clouds, for a satellite view of fallstreak holes. These gaps in the clouds are sometimes called hole-punch clouds. The holes form when supercooled water droplets (created when the temperature of a liquid or a gas goes below its freezing point without it becoming a solid) suddenly freeze - often when a plane flies through the cloud - and then fall. This leaves an opening in the formation as a result. Scientists are still gaining new insights on how fallstreak holes form and behave.