Fallstreak holes over Atlanta, Georgia Today’s Image of the Day from NASA Earth Observatory features large gaps in clouds known as fallstreak holes, which appear as a result of cold air temperatures and atmospheric instability.
The photo was captured on January 29, 2021 over the southern United States just west of Atlanta, Georgia.
According to NASA, both ascending and descending aircraft are a common trigger for fallstreak holes, and so it is no coincidence that the holes are often located near busy airport hubs.It is thought that the introduction of large numbers of tiny ice crystals into the cloud layer sets off this domino effect of fusion which creates the hole. The ice crystals can be formed by passing aircraft, which often have a large reduction in pressure behind the wing- or propeller-tips. This cools the air very quickly, and can produce a ribbon of ice crystals trailing in the aircraft’s wake. These ice crystals find themselves surrounded by droplets, and grow quickly by the Bergeron process, causing the droplets to evaporate and creating a hole with brush-like streaks of ice crystals below it. An early satellite documentation of elongated fallstreak holes over the Florida Panhandle that likely were induced by passing aircraft appeared in Corfidi and Brandli (1986). Fallstreak holes are more routinely seen by the higher resolution satellites of today (e.g., see second example image in this article).
Image Credit: NASA Earth Observatory