water
ice cover
The solid phase of water (H2O), and a mono-mineralic rock with an unusually low melting point.Several other important properties include (1) its polycrystalline structure with the ability to behave as a brittle solid yet also deform plastically under pressure; (2) its lower density than water, so that ice floats on water; (3) its volume change on formation from water, which results in expansion on freezing; (4) its low thermal conductivity, which makes ice and snow excellent insulators; (5) the bonding and shearing properties of snow, which are important in understanding the behaviour of snowpack and snow avalanches; and (6) the high reflectance of snow, hence its high albedo and involvement in feedback mechanisms affecting climate. The presence of ice in various forms is the defining material characteristic of the cryosphere. [Source: Encyclopedia of Environmental Change; ice]
ice
geomorphology
concepts