pyrocumulus clouds, huge fire clouds

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[EN VIDÉO] What causes forest fires in France?
Every year in France 15,000 hectares of vegetation go up in smoke. 90% of forest fires are of human origin and one in two are the result of carelessness.

the pyrocumulusa cloud formed Cauliflower that rises above thick smoke can rise above any source of heat a strong firework of forest, a volcanic eruptionbut also above a chimney industrial. Like everything cumulusit occurs when thesky of the lower layers of the atmosphere (at ground level) is warmer and more humid than those at high altitudes. When the air becomes saturated, the water vapor condenses into droplets to create a cloud.

Unlike other clouds, the heat source does not heat through the Sun, but another source of intense heat, coming from the ground. This cloud is officially recognized under the name cumulus flammagenitus by means of the international cloud atlasbut it is more commonly known as pyrocumulus.

The fire can generate its own weather

The pyrocumulus is the first stage of the development of this cloud, because under certain conditions weather forecastsuch as humidity in the atmosphere and currents in the air, it can quickly change into pyrocumulus congestus : a convective cloud, associated with instability. This one can develop more, and increase in height, then it becomes a pyrocumulonimbus. This pyrocumulonimbus is just a cloud ofthunderstorm which forms over the fire, fed by the heat of the fire. When it gains power, sometimes in just 30 minutes, this cloud can then generate lightning. In the most extreme cases, lightning can start new fires even nearby!

These pyrocumulonimbus can also cause: whirlwinds can lead to real fire tornadoes when smoke and flames from the fire are drawn in by the whirlwind. This kind of apocalyptic-looking situation, lightning and whirlwinds, occurs every year in the biggest fires on Earth, such as the one in California and D’Australia. Fires and volcanic eruptions can generate their own weather on the spot, sort of microclimate of short duration. Like any thundercloud, they can also lead to: wind which subsequently influence the behavior of the fire. They can also generate rain, but the heat from the fire causes the water to evaporate before it hits the ground.

Pyrocumulus can also form over an atomic explosion

The formation of pyrocumulus clouds over smoke or volcanoes is quite common, also in France, but not all are equally impressive. Need water vapor matter, from a core, to form the droplets necessary for cloud formation. the smoke of forest fires or volcanic ash adds a lot of material to the atmosphere and therefore increases the chance of cloud formation.

The same process takes place over the detonation of the nuclear weapon: the ” mushroom cloud that forms above the explosion of an atomic bomb is also a pyrocumulus cloud.

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