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And this is the second distrail of today, though it was much less spectacular than the previous one.
Distrail is the opposite of contrail. When the water vapour content of an airplane's exhaust gases fall under dew point, it freezes. If the air that the airplane passes through has the right temperature and moisture content, the ice crystals continue to grow and these supercooled waterdrops fall through the cloud below it, releasing their heat of fusion, and thus evaporating the surrounding cloud. A similar phenomenon is the hole-punch cloud. In this case the supercooled material probably originates from a higher cloud. In the photo below, you can see this latter phenomenon from 23rd August 2007. It's worth having a look at a photo by Kent Judkins (Shreveport, Louisiana) (EPOD), which depicts two beautiful oval hole punch clouds.