by Leslie Cox; Tuesday; February 11, 2025

This is an example of hoar frost which has formed on this broken piece of tree branch. Came across it on our walk with Sadie through a nearby forest recently…just a day or two before it started snowing.

Hoar frost forms when water vapour in the air comes into contact with solid objects which are already below the freezing point. Ice crystals from immediately and the ice continues to grow as more water vapour becomes frozen on the object. On a windless night it can grow well on tree and shrub branches where the surface temperature is not likely to rise above zero for several hours.