Out on my early walk this morning, I came across some hair ice fungus. This is a rare phenomenon as it needs exacting conditions. It needs moist air and temperatures just below 0°c and forms on broadleaf rotting wood, while mostly found in latitudes of 45°N and 55°N.
It occurs when the water in the wood freezes forming a barrier and trapping liquid between the pores and the ice creating a suction which pushes the water out of the wood and freezes, extending as it does. Therefore creating this beautiful silky, hair-like effect.