Extraordinary weather phenomenon: pyrocumulus clouds, huge fire clouds

the pyrocumulusa cloud shaped cauliflower which rises above thick smoke, can form above any source of heat strong: a fire of forest, a volcanic eruptionbut also above a chimney industrial. Like everything cumulusit occurs when theair of the lower layers of the atmosphere (at ground level) is warmer and more humid than that present at high altitude. When the air becomes saturated, the water vapor condenses into droplets to create a cloud.

Unlike other clouds, the heat source is not heating by the Sun, but another source of intense heat, which comes from the ground. This cloud is officially recognized under the name of cumulus flammagenitus by the international cloud atlasbut it is better known as pyrocumulus.

The fire is able to generate its own weather

The pyrocumulus is the first stage of the development of this cloud, because under certain conditions weather reportsuch as humidity in the atmosphere and currents aloft, it can quickly turn into pyrocumulus congestus : a convective cloud, linked to instability. This one can develop more, and gain in height, it then becomes a pyrocumulonimbus. This pyrocumulonimbus is simply a cloud ofthunderstorm that forms above the fire, fueled by the heat of the fire. When it gains power, sometimes in the space of just 30 minutes, this cloud can then generate lightning. In the most extreme cases, lightning can even start new fires nearby!

These pyrocumulonimbus are also capable of causing whirlwinds can lead to real fire tornadoes when smoke and flames from the fire are sucked in by the whirlwind. This type of apocalyptic-looking situation, lightning and whirlwinds, occurs every year in the largest fires on the planet, such as those in California and D’Australia. Fires and volcanic eruptions are actually able to generate their own weather on the spot, a sort of microclimate short-lived. Like any storm cloud, they can also cause winds which then influence the behavior of the fire. They can also generate rain, but the water evaporates before it even hits the ground due to the heat of the fire.

Pyrocumulus can also form above an atomic explosion

The formation of pyrocumulus clouds above smoke or volcanoes is quite common, including in France, but not all of them are necessarily impressive. Water vapor needs matter, of a nucleus, to form the droplets necessary for the formation of the cloud. The smoke of Forest fires or volcanic ash adds a lot of material to the atmosphere and therefore increases the likelihood of cloud formation.

The same process occurs above the detonation of the nuclear weapon: the ” mushroom cloud which forms above the explosion of an atomic bomb is also a pyrocumulus cloud.