Hoar frost on a spideweb

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 in 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.