What is "mushroom cloud"

Mushroom \Mush"room\, a.

1. Of or pertaining to mushrooms; as, mushroom catchup.

2. Resembling mushrooms in rapidity of growth and shortness of duration; short-lived; ephemerial; as, mushroom cities.

   Mushroom anchor, an anchor shaped like a mushroom, capable of grasping the ground in whatever way it falls.

   Mushroom coral (Zo["o]l.), any coral of the genus Fungia. See Fungia.

   Mushroom spawn (Bot.), the mycelium, or primary filamentous growth, of the mushroom; also, cakes of earth and manure containing this growth, which are used for propagation of the mushroom.

   mushroom cloud, a cloud of smoke rising and then spreading laterally to take on the shape of a mushroom -- caused by large fires or explosions, esp. nuclear explosions.

n. A large cloud of smoke, flame and debris that rises into the sky as a result of a large explosion, especially after a nuclear explosion, characterized by a long shaft rising from the ground into a much larger or more spread out top, reminiscent of a mushroom in shape.

n. a large cloud of rubble and dust shaped like a mushroom and rising into the sky after an explosion (especially of a nuclear bomb) [syn: mushroom, mushroom-shaped cloud]

A mushroom cloud is a distinctive pyrocumulus mushroom-shaped cloud of debris/smoke and usually condensed water vapor resulting from a large explosion. The effect is most commonly associated with a nuclear explosion, but any sufficiently energetic detonation or deflagration will produce the same sort of effect. They can be caused by powerful conventional weapons, like vacuum bombs, including the ATBIP and GBU-43/B Massive Ordnance Air Blast. Some volcanic eruptions and impact events can produce natural mushroom clouds.

Mushroom clouds result from the sudden formation of a large volume of lower-density gases at any altitude, causing a Rayleigh–Taylor instability. The buoyant mass of gas rises rapidly, resulting in turbulent vortices curling downward around its edges, forming a temporary vortex ring that draws up a central column, possibly with smoke, debris, or/and condensed water vapor to form the "mushroom stem". The mass of gas plus entrained moist air eventually reaches an altitude where it is no longer of lower density than the surrounding air; at this point, it disperses, any debris drawn upward from the ground scattering and drifting back down (see fallout). The stabilization altitude depends strongly on the profiles of the temperature, dew point, and wind shear in the air at and above the starting altitude.