Depth hoar

"Sugar snow" as a layer in a snowpack

Depth hoar crystals, imaged with light and with scanning electron microscopy

Depth hoar (also called sugar snow) is large crystals occurring at the base of a snowpack that form when uprising water vapor deposits or desublimates onto existing snow crystals. Depth hoar crystals are large, sparkly grains with facets that can be cup-shaped and that are up to 10 mm in diameter. Depth hoar crystals bond poorly to each other, increasing the risk for avalanches.

The formation of depth hoar in Arctic or Antarctic firn can cause isotopic changes in the accumulating ice. This can influence analysis of ice cores in scientific research.

External links

• The Avalanche Encyclopedia, extensive summary with animation of formation process