Ideal Conditions for Formation
In winter, when conditions are just right, ice resembling candy floss or fine silky hair forms on wet, dead branches in the forest. Known as ‘hair ice,’ the phenomenon has been reported mostly at latitudes between 45–55 °N in broadleaf or mixed forests, making southern British Columbia an ideal location for spotting it. But, can be difficult to find. The air must be just barely below freezing (0 C), while the dead wood must remain unfrozen and be free of bark. High humidity or damp conditions are required – and you have to be there at the right time to see it! The ice can last for days if it is not exposed to direct sun (or rain!) but disappears instantly with rain, or the warmth of a breath, touch, or sun.
The Secret Ingredient: Fungus
Hair ice was first described in 1918 by German geologist and climatologist Alfred Wegener. Wegener assumed some specific fungi as the catalyst. In 2015, Diana Hofmann, Gerhart Wagner, and Christian Mätzler identified the fungus Exidiopsis effusa as key to the formation of hair ice.
As thejelly-like fungus respires within the wood, it helps draw water through tiny pores to the surface. Molecules within the fungus act as a natural antifreeze, preventing the ice crystals from clumping together and instead encouraging the growth of delicate, hair-like strands rather than a dense layer of ice.
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Banner photo: Hair ice along the Mamquam spawning channel trails, 3:30 pm Jan 21, 2019, by Gwen L’Hirondelle.