Clear ice refers to a solid
precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...
which forms when
air temperature
Atmospheric temperature is a measure of temperature at different levels of the Earth's atmosphere. It is governed by many factors, including incoming solar radiation, humidity and altitude. When discussing surface air temperature, the annual ...
is between and and there are supercooled, relatively large
drops of
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...
(from freezing
fog
Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Reprint from Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influ ...
). 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
Freezing rain is rain maintained at temperatures below freezing by the ambient air mass that causes freezing on contact with surfaces. Unlike a mixture of rain and snow or ice pellets, freezing rain is made entirely of liquid droplets. The rain ...
or
drizzle
Drizzle is a light precipitation consisting of liquid water drops smaller than those of rain – generally smaller than in diameter. Drizzle is normally produced by low stratiform clouds and stratocumulus clouds. Precipitation rates from dri ...
hit a surface and is called
glaze. Clear ice, when formed on the ground, is often called
black ice
Black ice, sometimes called clear ice, is a thin coating of glaze ice on a surface, especially on streets. The ice itself is not black, but visually transparent, allowing the often black road below to be seen through it. The typically low level ...
, 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
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematicall ...
.
See also
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Ice storm
An ice storm, also known as a glaze event or a silver storm is a type of winter storm characterized by freezing rain. The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least of ice on ...
*
SAS Flight 751
References
External links
Gevi Ice Maker Info
{{ice
Water ice
Snow or ice weather phenomena