Fallstreak clouds are not clouds. They are downdrafts from the heat extraction vents of cloaked craft. Just thought you'd like to know…more.
It has to do with the dew point aloft. These so called fallstreak clouds appear in clear air also when the temp/dp spread is close and the air is cooled below the dew point, the water vapor becomes visible as it is squeezed out of the now cooler air. The dew point just means the temperature at which the air is 100% saturated with a given amount of suspended moisture.
The official explanation of ice crystals is absolute and utter bullshit to this 38 year commercial pilot.
Yw ; I've seen these fallstreak clouds in clear air where the temperatures were 40*F above freezing. Definitely NOT ice crystals. VERY few explanations except for something is cooling the air locally that can't be seen. When the known possibilities get ruled out, the unknown become probable.