A mushroom cloud is a distinctive post-bast pyrocumulus mushroom-shaped cloud of debris, hot air, gaseous vapour (usually condensed water vapour and usual air components like nitrogen gas) and smoke and resulting from the occurrence of a large explosion. The buoyant mass of gases, vapour and entrapped debris 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 vapour to form the "mushroom stem" as a skirt and bell form on it. When it cools and reaches a certain hight it will mostly fall back to earth as fall-out.
They are most commonly associated with nuclear explosions and atomic weapons going off on or near the ground, but any sufficiently energetic detonation or deflagration will produce the same sort of effect such as the conventional ATBIP, exploding arms depots, exploding arms ships, rocket flue factories, oil storage refinery tanks, massive gas works explosion and so on...
The intense radiation in the first seconds after an atomic blast, but not a non-nuclear blast, may also cause an observable aura of fluorescence, the blue-violet-purple glow of ionized oxygen and nitrogen out to a significant distance from the fireball, surrounding the head of the forming mushroom cloud. This light is most easily visible at night or under conditions of weak daylight. The brightness of the glow decreases rapidly with elapsed time since the detonation, becoming only barely visible after a few tens of seconds.
- POMCUS sites
- Atomic\nuclear war
- Nuclear fallout
- The atomic artillery peace ‘Atomic Annie’
- Atomic warfare information notes.
- Atomic accidents and disasters
- Geiger-Muller counter