Surely you have ever heard about the news on the rime. It is a meteorological phenomenon that occurs when fog freezes. For this phenomenon to be seen there must be some characteristics and some factors. Normally a time with low temperatures and persistent fog is needed. Despite the fact that it is a meteorological phenomenon that occurs in many places, it is not well known to people.

Therefore, we are going to dedicate this article to tell you all the characteristics of rim and why it happens.

What is rim

Forest with rime

Pablo VA - We are Palencia

It is a meteorological phenomenon that occurs when the fog freezes. When there is cold and persistent fog caused by high humidity, rime usually occurs. Many photographers take advantage of this type of phenomenon to take fascinating photos. It usually occurs in areas where there is dense fog and temperatures drop below 0 degrees. At these temperature values ​​the dew point is below freezing.

At this time is when the water levels that are floating in the air begin to freeze on the surfaces of the area. We remember that water needs a surface to freeze. Therefore, micron-sized sand particles are needed to act as a hygroscopic condensation core. When the water droplets begin to freeze on the surfaces they form feathers or needles of soft ice. These formations are similar to snow but they are not the same.

A place where a rumble has taken place is very similar to another place where it has snowed. However, if we approach the surfaces of rocks, tree branches, leaves, etc. We can see that these small needle and feather-like formations of ice caused by the frozen fog. The cities and towns of Spain that have a nearby river are the most candidates for this phenomenon to occur. It's one of the reasons why rime takes place frequently during winters in Valladolid or Burgos.

And it is that rivers are a constant source of humidity in the environment. In addition, thanks to the constant flow of water, a fairly dense flora develops that helps retain environmental humidity. When there are contrasts in day and night temperatures, this type of dense fogs usually occur and thanks to the flora it is usually retained. If the ambient temperature falls below 0 degrees, rime is more likely to occur.

Key features

Ice formed by rime

We see that once the rumble takes place it can happen in some ways. If the hydrometer happens at altitude and the temperature drops to 2 degrees below zero with the presence of wind, we see that the rime gets hard and the ice crystals are forming in a different way. These ice crystals do not have a formation process similar to the ice that occurs when there is snow, but instead creates a series of needles that grow in the direction of the wind. The longer the rime lasts and the conditions that favor it, the more ice will be able to accumulate.

Something that we should not confuse with rime is frost. It is a very common thing to confuse even two totally different phenomena. In order for the rumble to take place, it is essential that there is fairly dense fog in the environment. Frost occurs when the condensation of moisture itself in the environment. In this case, it is not necessary that there be fog, although it is true that a lot of humidity is needed in the environment.

Rime occurs when there are already foggy surfaces that are capable of retaining humidity from the environment. For this reason, it is more frequent in places where there is a river and flora associated with it. Surely, if it is the first time you see the rim, it may surprise you and say that it has a certain resemblance to snowy landscapes. It is evident that when the rime appears it is that the snow that has fallen is of great depth. This term is widely known in the interior of the Iberian Peninsula.

Why rim occurs


For this meteorological phenomenon to take place, clear skies are needed in winter, low temperatures and some place where it retains enough humidity. It is relatively frequent in mountain areas where there is a river and flora associated with it. It is mainly called as an ice deposit formed by the freezing of fog droplets or low-lying clouds. It can be said that the fog is nothing more than low clouds at the surface level.

For this phenomenon to take place a temperature below freezing is required. This is how morning fogs are produced with great frequency in places of valleys, especially. The main consequence for this phenomenon to occur is night-time cooling by radiation. For this, there needs to be a large difference between daytime and nighttime temperatures.

The conditions necessary for the rumble to take place are clear skies, absence of wind, great contrast between day and night temperatures and that the temperatures during the morning are lower or slightly higher than 0 degrees. If all these environmental conditions are metWe probably have a common morning fog that will turn rime. It is more common in river valley areas with high relative humidity and low temperatures.

Nighttime temperatures must be very low and relative humidity very high. The humidity generated by cloudiness must be located at ground level, which will cause it to turn into ice when it rubs against the surfaces. The cold air tends to descend from the slopes and contributes a greater amount of humidity that facilitates the formation of fogs. This high relative humidity is what helps to provide the necessary water for the formation of the fog that, later, freezes on the surface.

I hope that with this information you can learn more about rim.

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  1.   Hugo Balls said

    How much typing error, that nobody edits these things?