Also called TG (temperature Gradient) Snow, the bane of backcountry skiers. A weak layer of poorly bonded snow which may or may not be visible upon digging a snow pit. Depth Hoar is commonly formed/found in early winter, and is more prevalent in the continental Rockies than in the pacific coast ranges. Depth Hoar greatly increases avalanche risk, making some regions unsafe until spring, and melt/freeze metamorphosis takes place
Large-grained, faceted, cup-shaped crystals near the ground. Depth hoar is caused by large temperature gradients within the snowpack, usually in the early winter, by large temperature differences between the warm ground and the cold snow surface.
Ice crystals (usually cup-shaped, faceted crystals) of low strength formed by sublimation within dry snow beneath the snow surface; a type of hoarfrost. Associated with very fast crystal growth under large temperature gradients. This is one way in which firn formation may begin. Depth hoar is similar in physical origin to crevasse hoar Hoarfrost composed of crystals that have built up a three-dimensional complex of faceted, rather than rounded, crystals.