Hoarfrost: It's Not as Naughty as it Sounds

There is nothing more gorgeous than waking up on a cold winter morning to the sight of naked tree limbs or evergreen trees covered in what appears to be snow. But it hasn't snowed, and upon closer examination, the crystals on the trees are too large to be snow flakes. It's actually hoarfrost.

Hoarfrost occurs when there is high humidity in the air and the tree limbs (or grass or even the antenna on your vehicle) have a temperature below the Dew Point. The water vapor from those surfaces skips the dew process and goes directly to a frozen state.

The official definition of hoarfrost from the National Weather Service is "a deposit of interlocking crystals formed by direct sublimation on objects, usually those of small diameter freely exposed to the air, such as tree branches, plants, wires, poles, etc."

Hoarfrost is a general term for this kind of frost. Its specific name depends on where the frost forms. For example, according to Wikipedia, air frost refers to the frost formation upon objects in the air, such as tree branches, wires, and plant stems; surface hoar is frost deposited directly upon the snow and other frozen surfaces; and depth hoar is formed beneath the surface within dry snow.

I know that some of you out there were thinking hoarfrost was some sort of prostitute popsicle. So where does the odd term come from?

In researching this, I found differing information. According to Dictionary.com, the Online Etymology Dictionary says the word 'hoar', as it pertains to frost, "It is recorded in O.E. (hoar-frost is c.1290), expressing the resemblance of the white feathers of frost to an old man's beard." The word itself came from the Proto-Germanic (P.Gmc) word har meaning "grey, venerable, old". The Germans still retain this word in the form of Herr, which is a title of respect.

Dictionary.Die.net reports that the definition of the word 'hoar' can mean anything from grey and old to moldy and musty. Yet, as far as where the word comes from, the Old High German (OHG) form means "illustrious, magnificent". It is my opinion it is this OHG origin that gave the beautiful hoarfrost its name.

The rare instances of hoarfrost really makes living in North Dakota, and waking up to frigid temperatures, a little more bearable. The way the sun sparkles off the ice crystals, especially when against a bright blue sky, is comparable to millions of diamonds dripping off the dead, naked, twisting tree limbs.

Sources:
http://weather.thefuntimesguide.com/2007/12/the_mystery_of_hoar_frost.php
http://dictionary.die.net/hoar
http://dictionary.reference.com/browse/hoarfrost
http://en.wikipedia.org/wiki/Frost#Hoar_frost