Hair IceI was lucky enough to spot this 'Hair Ice' on a rotting branch at Beggar’s Bridge in Glaisdale in December.
It's an uncommon sight because of the specific conditions under which it forms. First, it only occurs on rotting wood hosting the thin jelly fungus Exidiopsis effusa. Second, it needs specific conditions of environment and weather: a damp place where the temperature has suddenly dropped to just under 0° C.
Alfred Wegener first proposed the connection between Hair Ice and fungus in 1918 but it took a century for a group of German scientists to study the process in detail, involving 'ice segregation' on the wood surface, whereby traces of lignin and tannin, released during fungal decomposition, are sucked into the ice crystals. Hair Ice can grow up to 20 cm and form spectacular 'tresses'. Mine was a more modest example of around 5 cm, but still an exciting find.
Met Office. Hair Ice.
SCI-NEWS website (2015). European Biologists Finally Solve Mystery of Hair Ice.
Helen Kitson, 1 January 2022