@johnjohnston There was a feature on that on Winterwatch recently. Apparently it is called ‘hair ice’ and is very rare.
@johnjohnston Someone’s posted the episode to YouTube. Have a look at this from about two minutes in. Apparently the twig it grows on needs to be infected by a specific fungus for the phenomenon to occur.
@adoran2 that was amazing, especially the timelapse. What a strange phenomenon. The mix of prerequisites is mind boggling.