What happens when you combine fungus, near 100% humidity, rotting alder branches and a frosty winter morning?
Hair frost!
It may look like cotton candy or like some sort of very strange mold, but these hair-like structures are actually ice.
Here's what Britain's weather service has to say:
The
conditions required for the formation of hair ice are extremely specific, hence
the relative scarcity of sightings. 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.In 2015 the scientists Hofmann, Mätzler and Preuß determined the exact cause of the hair ice phenomenon, linking its formation to the presence of a specific fungus called Exidiopsis effusa.
They 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.
I photographed this hair ice on the Eastern edge of Capitol Forest near the pond at McLane Creek Nature Trail. I arrived shortly after 9 AM. When I left at 11:30 AM, all evidence of the morning's hair-raising experience had disappeared.
Many thanks to my friend KV, who clued me in on this neat natural phenomenon
To see a time-lapse video of hair ice forming at the Hoh Rainforest, click here. The video was made by Matt Nichols (camitolympicmedia)
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