People have long been fascinated by unusual formations known as "hole-punch clouds," such as this cloud over Alabama. Recent research led by the National Center for Atmospheric Research has documented the role of aircraft in creating these clouds and the precipitation associated with them.
As turboprop and jet aircraft climb or descend under certain atmospheric conditions, they can inadvertently create a cooling effect in mid-level clouds, transforming water droplets into ice. These newly created ice particles fall out of the sky as snow or rain. They leave behind odd-shaped holes or channels.
