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HAIR ICE : Exidiopsis effusa 

This is more a phenomenon than a fungus. This is an extraordinary process. As the Met Office notes. Hair ice is a rare type of ice formation where the presence of a particular fungus in rotting wood produces thin strands of ice which resemble hair or candy floss.

Our example is one of several seen in Fishers Wood in February 2024, the weather at the time fitting the requirements noted for its formation. 

To form, moist rotting wood from a broadleaf tree is required with the presence of moist air and a temperature slightly below 0 °C. It is generally confined to latitudes between 45°N and 55°N.

Isn't it strange that the Met Office is our main source of information on this fungus, or rather the effect of the fungus.

Researchers discovered that the presence of the fungus led to a process called 'ice segregation'. When water present in the wood freezes it creates a barrier that traps liquid between the ice and the pores of the wood. This creates a suction force which pushes water out of the pores to the edge of the ice surface where it freezes and extends outwards. As this repeats it pushes a thin 'hair' of ice out of the wood which is around 0.01 mm in diameter.

It is believed that an inhibitor present in the fungus allows the strands of ice to stabilise allowing the formation of the beautiful phenomena and allows the hair ice to keep its shape often for several hours. [Met Office]. 

It is soft to the touch and very friable. 

At first glance this looks much like other white fungus.

but on closer inspection it looks like white fur.

METEORLOGICAL OFFICE : https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/frost-and-ice/hair-ice


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