Search results
Results from the WOW.Com Content Network
Hoar frost, also hoarfrost, radiation frost, or pruina, refers to white ice crystals deposited on the ground or loosely attached to exposed objects, such as wires or leaves. [3] They form on cold, clear nights when conditions are such that heat radiates into outer space faster than it can be replaced from nearby warm objects or brought in by ...
A heavy coating of hoar frost, called white frost, is very similar in appearance to soft rime, but the formation process is different; it happens when there is no fog, but very high levels of air relative humidity (above 90%) and temperatures below −8 °C (18 °F). Soft rime formations appear as narrow white icy needles and scales.
The three main types of ground frost are radiation frost (), advection frost (advection hoar frost) and evaporation frost.The latter is a rare type which occurs when surface moisture evaporates into drier air causing its temperature at the surface to fall at or under the freezing point of water. [1]
Printable version; In other projects Appearance. move to sidebar hide. From Wikipedia, the free encyclopedia. Redirect page. Redirect to: Frost#Hoar frost;
Freezing [1] or frost occurs when the air temperature falls below the freezing point of water (0 °C, 32 °F, 273 K). This is usually measured at the height of 1.2 metres above the ground surface. This is usually measured at the height of 1.2 metres above the ground surface.
In the foreground are hoar frost crystals, formed by refrozen water vapor emerging to the cold surface. Sastrugi formed during a blizzard just a few hours earlier. According to the International Association of Cryospheric Sciences, snow metamorphism is "the transformation that the snow undergoes in the period from deposition to either melting ...
More generally, water vapor depositing onto surfaces due to high relative humidity and then freezing results in various forms of atmospheric icing, or frost. Inside buildings, this can be seen as ice on the surface of un-insulated windows. [94] Hoar frost is common in the environment, particularly in the low-lying areas such as valleys. [95]
This is how frost and hoar frost form on the ground or other surfaces. Another example is when frost forms on a leaf. For deposition to occur, thermal energy must be removed from a gas. When the air becomes cold enough, water vapour in the air surrounding the leaf loses enough thermal energy to change into a solid.