Blue Sky Above Frost Tipped Winter Trees Stock Image

After a cold, clear winter night without much wind, the ground and nearby tree branches may be covered by tiny, white ice crystals. These loosely interlocked ice crystals are a phenomena known as hoarfrost or radiation frost. This frost is formed from the same process that forms dew; however, the liquid stage is skipped completely. Basically the air cools to the dew point and, because the surface temperature of the object is already below freezing, crystals are formed. In order for this frost to form it is essential that the air is warmer than the objects in which the frost forms upon. These ice crystals are relatively rare but can be mistaken for snow depending on their thickness. Hoarfrost can form on various forms of vegetation or objects that are in the open air and have been cooled below the freezing point. These objects can include leaves, plants, wires, poles, tree branches, blades of grass and twigs. Other places this unique frost can be found are man-made. Despite its natural beauty, hoarfrost is also known to help cause avalanches.