From Old Norse stormr (“storm”), from Proto-Germanic *sturmaz, from Proto-Indo-European *(s)twer-, *(s)tur- (“to rotate, swirl, twirl, move around”).

From Old Norse nepja (“chilliness, bitter cold”), from napr (“cold, chilly”) whence the Icelandic napur.

Old English forst, frost “frost, a freezing, frozen precipitation, extreme cold,” from Proto-Germanic *frustaz “frost” (source also of Old Saxon, Old Frisian, Old High German frost, Middle Dutch and Dutch vorst), from the verb *freusanan “to freeze” (source of Old English freosan “to freeze”), from suffixed form of PIE …

Muspelheim

Frost is defined as to cover with icing or a layer of ice crystals. An example of frost is putting a layer of chocolate buttercream over the top and sides of a cake. An example of frost is a below freezing night resulting in a layer of frost on the windshield of your car.

After condensation the water vapour or the moisture in the atmosphere takes one of the following forms — dew, frost, fog and clouds.

Its root is taken from the old English adjective “hoary” which means, gray or white in appearance. This word was often used to describe a person of age who had white hair and a white beard. Knowing this, it now makes sense how one would look at a frost-covered tree in that age and call the frost covering it hoarfrost.

Rime ice often happens in areas of dense fog, like we have seen the past couple of nights. Hoar frost is similar to dew and happens on cold and clear nights. This is when water vapor (which is a gas) freezes onto a below-freezing surface.

With rime, the moisture comes from freezing fog water droplets that turn directly from a liquid state to a solid state, or through direct freezing. On the other hand, hoar frost occurs on a clear, cold night where water vapor sublimates: transitioning immediately from a gaseous state to a solid state.

pogonip

According to the National Weather Service, hoar frost is defined as a “deposit of interlocking crystals formed by direct sublimation on objects, usually those of small diameter freely exposed to air, such as tree branches, plants, wires, poles, etc.”

Hoarfrost, deposit of ice crystals on objects exposed to the free air, such as grass blades, tree branches, or leaves. It is formed by direct condensation of water vapour to ice at temperatures below freezing and occurs when air is brought to its frost point by cooling.

Rime ice is not a rare phenomenon, but it doesn’t usually build up over several days, says meteorologist John Gagan to Joe Taschler at the Milwaukee Journal Sentinel. Foggy weather means that the landscape was immersed in water droplets suspended in the air.

When freezing fog occurs, it can cause ice buildup on roads, creating dangerous driving conditions, especially on bridges, which will freeze first because they have no ground insulation. Because freezing fog will freeze on any surface, it often builds up on power lines and can cause power outages.