What is fog?

Fog

Fog is a collection of liquid water droplets or ice crystals suspended in the air at or near the Earth's surface. While fog is a type of stratus cloud, the term "fog" is typically distinguished from the more generic term "cloud" in that fog is low-lying, and the moisture in the fog is often generated locally (such as from a nearby body of water, like a lake or the ocean, or from nearby moist ground or marshes). Fog is distinguished from mist only by its density, as expressed in the resulting decrease in visibility: Fog reduces visibility to less than 1 km (5/8 statute mile), whereas mist reduces visibility to no less than 1 km . For aviation purposes in the UK, a visibility of less than 5 km but greater than 999 m is considered to be mist if the relative humidity is 70% or greater – below 70% haze is reported..

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Famous quotes containing the word fog:

    Even as fog continues to lie in the valleys, so does ancient sin cling to the low places, the depressions in the world consciousness.
    Dewitt Bodeen (1908–1988)

    The brown waves of fog toss up to me
    Twisted faces from the bottom of the street,
    And tear from a passer-by with muddy skirts
    An aimless smile that hovers in the air
    And vanishes along the level of the roofs.
    —T.S. (Thomas Stearns)

    as if in a fog of feather-light
    goosedown-silvery seed-thoughts
    a rusty mind in its autumn
    reviewed, renewed
    its winged power.
    Denise Levertov (b. 1923)