Ice Crystals dangling


Rime refers to a coating of ice. It is the buildup of ice usually in the form of small white crystals which occurs when small liquid droplets freeze upon making contact with a cold surface.

There are two types of rimes depending on how they occur. These are hard rime and soft rime.

What is hard rime?

Trees with hard rime on them

Hard Rime Source: Marcin Sochacki via Wikipedia

Hard rime refers to a unique form of white ice that forms when droplets of water that is found in fog freezes. Is visible to the outer surfaces of objects. If you are searching for hard rime, you will most likely see them at the top of trees high up in mountains and high ridges during the winter. It is a time when low clouds create freezing fog.

Hard rime usually freezes along the sides facing the wind among trees, buildings, and any other solid objects. For hard rime to form, it requires an air temperature that is less than 29 degrees Fahrenheit. In most cases higher than 17 degrees Fahrenheit will cause it. It is important to know that high winds always accompany the formation of hard rime.

While soft rime appears more feathery or spiky, hard rime possesses a comb-like appearance. It is very dense, less milky in color, compared to soft rime. Although it can sometimes be milkier when it is heavy.  Typically, the level of supercooled water droplets is the factor that determines the type of ice that forms. In this case, hard rime has the least while soft rime and clear ice follow suit. It is sure that the more the quantity of water droplets found in ice, the denser it becomes. As for hard rime, it is typically made up of fewer water droplets and lots of ice crystal.

Soft Rime

Soft rime, on the other hand, is a whitewater deposit that forms when the water droplets that exist in mist or light freezing fog freezes to the outer surfaces of objects, by the calm or light wind. The fog that makes up soft rime also freezes to the windward side of trees, wires or such other solid objects

A branch showing Soft Rime crystals

Soft Rime Source: Softrime2006 via Wikipedia

Soft rime shares similar characteristics with hoar frost. Except rimes are formed when vapor first condenses to liquid droplets such as fog, mist or cloud, to a freezing surface. Meanwhile, hoar frost is formed by the direct deposit of water vapor turning into solid ice. White frost is a heavy coating of hoar frost, which looks much like soft rime, but forms differently.

During formations, soft rime has the appearance of white ice needles and scales. These are usually fragile and can easily be shaken off objects. Rime is formed when supercooled liquid hits a frozen surface. Any different condition in line with the factors as mentioned earlier dramatically favors ice with higher densities like clear ice or hard rime.

Another awesome winter weather phenomenon.  So many amazing weather anomalies on the earth.  Just look around you.

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