The Ice That Grows Like Hair
On winter mornings in some forests, dead branches sprout soft, white, silky hair that melts in your hand.
What was reported
On humid winter nights, with the temperature just below freezing, fine white hair can grow out of rotting branches of broadleaf trees in forests in Europe and elsewhere. It looks like candyfloss, cotton wool or an old man's beard, and each strand is thinner than a human hair but can be several centimetres long.
In 1918, Alfred Wegener, better known for the theory of continental drift, suggested a fungus was responsible, because the ice grew only on certain dead wood.
Explanations offered
In 2015, scientists showed that Wegener was right: hair ice forms only where a particular fungus, Exidiopsis effusa, lives in the wood. The fungus seems to release substances that stop the ice from forming large crystals, so it is pushed out of tiny pores in the wood as fine, curling threads.
- When
- Described by Alfred Wegener in 1918; explained in 2015
- Where
- The Black Forest, Baden-Württemberg, Germany
- Witnesses
- Forest walkers and scientists
- Status
- Explained
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