Mist is a phenomenon caused by small droplets of water suspended in the cold air, usually bycondensation. Physically, it is an example of adispersion. It is most commonly seen where water vapor in warm, moist air meets sudden cooling, such as inexhaled air in the winter, or when throwing water onto the hot stove of asauna. It can be created artificially with aerosol canisters if thehumidity and temperature conditions are right. It can also occur as part of natural weather, when humid air cools rapidly, notably when the air comes into contact with surfaces that are much cooler than the air (e.g. mountains).
The formation of mist, as of othersuspensions, is greatly aided by the presence ofnucleation sites on which the suspended water phase can congeal. Thus even such unusual sources of nucleation as small particulates fromvolcanic eruptions, releases of strongly polar gases, and even themagnetospheric ions associated withpolar lights can in right conditions trigger condensation and the formation of mist.
Mist is commonly confused withfog, which resembles astratus cloud lying at ground level. These two phenomena differ, but share some commonalities; similar processes form both fog and mist. Fog is denser, more opaque, and generally lasts a longer time, while mist is thinner and more transparent.
Cloud cover is often referred to as "mist" when encountered on surfaces of mountains, whereas moisture suspended above a body of water, cleared or marsh area is usually called "fog".[citation needed] One main difference between mist and fog isvisibility.[1] The phenomenon is called fog if the visibility is 1 km (1,100 yd) or less. In the United Kingdom, the definition of fog is visibility less than 100 m (330 ft) on the surface for driving purposes,[2] while for pilots the distance is 1 km at cruising height. Otherwise, it is known as mist.
Mist makes a light beam visible from the side viarefraction andscattering on the suspended water droplets, andrainbows can be possibly created.
"Scotch mist" is a light steady drizzle that appears like mist.
Mist usually occurs near the shores and is often associated with fog. Mist can be as high as mountain tops when extreme temperatures are low and strong condensation occurs.
Freezing mist is similar tofreezing fog, only the density is less and the visibility greater. When fog falls below 0°C, it is known as freezing fog, however it still stays suspended.[3]
