Clear ice

For ice cubes, see Ice cube § Clear and cloudy.

Clear ice can form in nature as a solid precipitation which forms when air temperature is between 0 °C (32 °F) and −3 °C (27 °F) and there are supercooled, relatively large drops of water (from freezing fog). A rapid accretion and a slow dissipation of latent heat of fusion favor the formation of a transparent ice coating, without air or other impurities. A similar phenomenon occurs when freezing rain or drizzle hits a surface and is called glaze. Clear ice, when formed on the ground, is often called black ice, and can be extremely hazardous.

Clear ice is denser and more homogeneous than hard rime; like rime, however, clear ice accumulates on branches and overhead lines, where it is particularly dangerous due to its relatively high density.

Clear ice can also form naturally in bodies of water during cold temperatures, due to dissolved gases being forced downward into the still liquid water as the ice forms.

Some specialized ice makers make use of directional freezing in order to produce clear ice for use in beverages and ice sculptures.

See also

• Ice cube#Clear and cloudy
• Ice storm
• SAS Flight 751