The natural phenomenon 'hair ice' – sometimes also called 'King Winter's beard' – can be spotted across Belgium these days. The phenomenon is rare as the weather conditions have to be just right for it to form.
During a walk in the Sonian Forest, hiker Anne Ceyssens accidentally came across ice hair, several people spotted the hair ice. It was also spotted in Antwerp and several other places across the country.
"I had seen photos of it before and read articles about it, but I had never come across it myself. Until yesterday. It was the gift of the day," she told VRT.
Rare phenomenon
Hair ice is a rare natural phenomenon because it only occurs in very specific circumstances: the temperatures must be below freezing, but not too much – around -4°C – while the humidity should be high enough. Only in these conditions can hair ice form on dead branches that contain a specific type of fungus.
The metabolism of fungi in the wood releases water, which is pressed out. This process produces a little heat, which prevents the wood and the water from freezing – until the water comes into contact with the cold outside air.
Because the humidity is so high, the water does not evaporate or volatilise, but freezes in the light frost. It is pressed out through fine holes in the wood, which creates all kinds of fine ice hairs. These also become longer and longer, because more and more water is separated.
It should not freeze too hard for this process: if it is too cold, the fungi's metabolism drops back to a level that is too low to produce enough water.
As temperatures will remain slightly below zero on Sunday night, people will likely see more hair ice on Monday. It is best to start looking early in the morning, as hair ice is very fragile and melts away immediately when it comes into contact with the sun or when the temperature rises above freezing.
Good to know: ice hair only grows on deciduous trees, especially oaks and beeches, because the fungus only grows in those trees. The fungi help break down dead wood, so that it can be reabsorbed into the food cycle.
Many photos of ice hair in the Netherlands have also surfaced on social media in recent days.
