EARTH SCIENCE > CRYOSPHERE > FROZEN GROUND
Soil within which the moisture has predominantly changed to ice, the unfrozen
portion being in vapor phase.
Ice within the soil bonds (adfreezes) adjacent soil particles and renders
frozen ground very hard. Permanently frozen ground is called permafrost. Dry
frozen ground is relatively loose and crumbly because of the lack of bonding
ice. Frozen ground is sometimes inadvisedly called frost or ground frost.
American Meteorological Society Glossary of Meteorology Online