Eeva Suula, a resident of the medieval town of Ulvila in western Finland was in for a surprise when she encountered icy wreaths wrapped around dead branches during a forest trek with her family.
"At first I didn’t believe it when what my husband claimed was dog hair melted at his touch. I had to try it myself," Suula said.
According to Yle meteorologist Seija Paasonen, what Suula’s family saw was not a sign that gnomes really do exist in the forest, but a natural phenomenon called ice hair, ice wool or snow beard.
"I have often seen it myself in the forest on branches lying on the ground, when the air temperature is slightly below zero. Water vapour is released from fungal growths inside the decaying wood and can be seen on the surface of the wood. ”Hairs” form as the process continues," Paasonen explained.
The forest trekker said that she had never heard of ice hair.
"The meteorologist’s explanation makes sense, the branches were probably decaying. The ice hair was baffling and a new experience for the entire family," she added.
According to Paasonen, the phenomenon requires a fungal colony growing inside a rotting piece of timber as well as calm conditions with temperatures just below freezing. The fungal growths do not take root in conifers, however.
The mystical snow beard growths are more prevalent in hardwood forests in central Europe. The first sightings of the interplay between wintry conditions and dying trees occurred about five years ago in Finland.
"As the wood freezes, the moisture inside it is pushed out by capillary forces. There are countless fungal colony heads on the surface of the wood, and a fine, icy hair begins to form on each of them," lead hydrologist Esko Kuusisto of the Finnish Environment Institute (Syke) told Yle at the time.
"It needs to be cold enough for the frost to penetrate far enough into the tree," he added.
Ice hair can grow to lengths of dozens of centimetres, at which point it can even begin to curl.
The first scientific observations of the phenomenon occurred in the United States in 1833.