Rime (frost)
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Rime ice is a white ice that forms when the water droplets in fog freeze to the outer surfaces of objects. It is often seen on trees atop mountains and ridges in winter, when low-hanging clouds cause freezing fog. This fog freezes to the windward (wind-facing) side of tree branches, buildings, and any other solid objects.
It looks quite similar to hoar frost, but rime ice is formed by vapour first condensing to liquid droplets (of fog, mist or cloud) and then attching to surface, while hoar frost is formed by direct sublimation from water vapour to solid ice.
Scientists at places like Mount Washington in New Hampshire often have to break huge chunks of rime ice off weather equipment, in order to keep anemometers and other measuring instruments operating.
Sometimes the rime ice takes on a feathery look, and looks very much like "snow feathers".
Ice storms may be comprised of either glaze ice or rime ice. Meteorologists classify transparent and homogeneous ice forming on vertical and horizontal surfaces as glaze. Glaze ice resembles ice-cube ice in appearance. Its amorphous, dense structure helps it cling tenaciously to any surface on which it forms. In contrast, if the ice is milky and crystalline, like sugar, it is termed rime. Rime ice is less dense than glaze ice and clings less tenaciously, therefore damage due to rime is generally minor compared to glaze ice.
Rime ice and glaze ice are also the two types of ice that can form on the surfaces of an aeroplane, if it flies though a cloud made of suporcooled water liquid droplets.
Rime ice is formed also inside of your freezer, while when you take objects out of freezer on a humid summer day, hoar frost is formed on their surfaces in a while.de:Reif (Niederschlag) eo:Prujno pl:Szadź fi:Huurre