Hoar Frost

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I’d like to publicly state something. I LOVE LOVE LOVE it when people tell me that they saw something beautiful, different or odd and they say they thought of me. What greater honor than to be tied to moments that are truly exceptional. What I love only slightly more is when people call and tell me about such things and I have time to get there to see and capture it for myself. Such was the case yesterday when my step-sister informed me of the remarkable frost phenomena happening at her place. I was fortunate enough to convince the boss lady that the journey to explore said phenomena was worthy of the afternoon away from the office. So off I went. The fog didn’t roll in until the day’s light had almost left us, but the air was still and I was able to capture some truly unique images.

Quoth the all powerful Wikipedia:

Hoar frost (also called radiation frost or hoarfrost or pruina) refers to the white ice crystals, loosely deposited on the ground or exposed objects, that form on cold clear nights when heat is lost into the open sky causing objects to become colder than the surrounding air. A related effect is flood frost or frost pocket which occurs when air cooled by ground-level radiation losses travels downhill to form pockets of very cold air in depressions, valleys, and hollows. Hoar frost can form in these areas even when the air temperature a few feet above ground is well above freezing. Nonetheless the frost itself will be at or below the freezing temperature of water.

Hoar frost may have different names depending on where it forms. For example, air hoar is a deposit of hoar frost on objects above the surface, such as tree branches, plant stems, wires; surface hoar is formed by fernlike ice crystals directly deposited on snow, ice or already frozen surfaces; crevasse hoar consists of crystals that form in glacial crevasses where water vapour can accumulate under calm weather conditions; depth hoar refers to cup shaped, faceted crystals formed within dry snow, beneath the surface.

The name hoar comes from an Old English adjective for showing signs of old age, and is used in this context in reference to the frost which makes trees and bushes look like white hair. It may also have association with hawthorn when covered in its characteristic white spring blossom.

 

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