Black ice is ice that is transparent. It has different meanings depending on context, but is most often used to refer to highway ice that increases the risk of accidents. Black ice may mean : Black ice, hazardous frozen water Black Ice (poet), a poet from Russell Simmons Def Poetry Jam. ... Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ... See: transparency (optics) alpha compositing GIF#Transparency transparency (overhead projector) market transparency transparency (telecommunication) transparency (computing) For X11 pseudo-transparency, see pseudo-transparency. ...

On highways

Black ice, also known as "glare ice" or "clear ice", typically refers to a thin coating of glazed ice on a surface, often a roadway. While not truly black, it is transparent, allowing the usually-black asphalt/macadam roadway to be seen through it, hence the term. It also is unusually slick compared to other forms of ice on roadways.^{[citation needed]} Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ... Unlucky black cat. ... See: transparency (optics) alpha compositing GIF#Transparency transparency (overhead projector) market transparency transparency (telecommunication) transparency (computing) For X11 pseudo-transparency, see pseudo-transparency. ... Base layer of asphalt concrete in a road under construction. ... Macadam is a type of road construction pioneered by John Loudon McAdam in the early 1800s. ...

It is usually deposited by extremely cold rain droplets, mist, or fog. The process of freezing is slowed down due to latent heat given off in sublimation, allowing the rain droplets to flow and merge together on the surface forming a film before freezing into clear ice. Nevertheless, because it contains relatively little entrapped air in the form of bubbles, black ice is transparent and thus very difficult to see (as compared to snow, frozen slush, rime ice, or other typical forms of ice on roadways). In addition, it often has a matte appearance rather than the expected gloss; and often is interleaved with wet pavement, which is identical in appearance. For this reason it is especially hazardous when driving or walking because it is both hard to see and extremely slick. Rain falling Rain is a form of precipitation, other forms of which include snow, sleet, hail, and dew. ... Dramatic morning mist Mist is a phenomenon of a liquid in small droplets floating through air. ... Evening fog obscures Londons Tower Bridge from passers by. ... In physics and chemistry, freezing is the process of cooling a liquid to the temperature (called freezing point) where it turns solid. ... This article or section does not cite its references or sources. ... Sublimation of an element or substance is a conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage. ... Rain falling Rain is a form of precipitation, other forms of which include snow, sleet, hail, and dew. ... In physics and chemistry, freezing is the process of cooling a liquid to the temperature (called freezing point) where it turns solid. ... Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ... Layers of Atmosphere (NOAA) Air redirects here. ... Soap bubbles Bubble may refer to: Soap bubble, spherical liquid film, also possibly of bubble gum Cavitation, pocket of air caught in a liquid Bubble (economics), where speculation causes prices to rise to unsustainable levels a (normally) transparent dome Light bulb, in theater lighting terminology [1] in poker tournaments, the... For other uses, see Snow (disambiguation). ... Slush is partly melted snow and ice. ... Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ...

Black ice may form even when the ambient temperature is several degrees above the NTP freezing point of water. This occurs typically (and treacherously) when terrain contours and/or prevailing winds cause a local steep differential of atmospheric pressure and/or temperature, or when the atmosphere has warmed up after a prolonged cold spell that leaves the temperature of the ground and roadway well below the freezing point. Room temperature, in laboratory reports, is taken to be roughly 21–23 degrees Celsius (68–72 degrees Fahrenheit), or 294–296 kelvins. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... Water is a chemical substance that is essential to all known forms of life. ... Look up Contours in Wiktionary, the free dictionary. ... The prevailing winds are the trends in speed and direction of wind over a particular point on the earths surface. ...

Bridges and overpasses can be especially dangerous. Black ice forms first on bridges and overpasses because air can circulate both above and below the surface of the elevated roadway, causing the temperature to drop more rapidly than on regular pavement.

"Black ice" may also be cited as the cause of a car crash when, in fact, the real root cause may have been excessive speed, inattention, or some other fault on the part of the driver. A root cause is a cause that is at a root of an effect. ...

Ice skating

In northern New England, black ice traditionally was a clear type of pond ice that forms in very cold weather. Black ice has the appearance of thick, slightly cracked glass laid on the water, and its transparency reveals the darkness of the pond beneath; hence the name. Black ice is very hard and smooth, and provides conditions that make ice-skaters ecstatic: effortless gliding and extremely smooth, if slow, stopping. (One can skate sideways on black ice, using the right blade angle.) The states marked in red show New England. ...

Maritime black ice

Black ice is a danger for cold-weather fishing trawlers. As ice forms on its superstructure, a boat can become too heavy, and in rough weather this unbalanced extra weight may capsize it. Thick layers of black ice can form rapidly on boats where they encounter a combination of air temperatures cold enough to freeze seawater and rough seas that splash seawater over the entire boat. Categories: Water-transport stubs | Ship types ... // Sociological concept In social sciences, superstructure is the set of socio-psychological feedback loops that maintain a coherent and meaningful structure in a given society, or part thereof. ... Annual mean sea surface temperature for the World Ocean. ...

External links

• Is there really such a thing as black ice?, from the Straight Dope staff