Hair ice (in German Haareis) is formed at dead wood by conditions of high humidity and temperatures near freezing point. Water in the pores expands below 4°C and freezes on the surface. In this way fine ice needles were created.
A frost flower is a name commonly given to a condition in which thin layers of ice are extruded from long-stemmed plants in autumn or early winter. The thin layers of ice are often formed into exquisite patterns that curl into "petals" that resemble flowers.