Frost

Frost forms at temperatures below  0°C,  due to the dew that freezes or due to direct precipitation of small ice needles.
Rime, which is known as galaverna in a dialect of Northern Italy, is a particular form of frost, characterized by large needle-shaped ice crystals which may be transported by the wind, and cover all the surfaces following their contours in their finest detail, as for example blades of grass, twigs, electric wires and antennas.
Frost too, belongs to the category of occult precipitations. It can melt and evaporate during the course of the day, or it may remain on the ground for various days, depending on the temperatures. If frost deposits on snow and is then covered by snowfall, a level of ice crystals may form within the layer of snow that is not very coherent, and may cause the release of slab avalanches.

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