What are Pyrocumulonimbus Clouds?

What is a Cumulonimbus Cloud (Cb)?

• It is a heavy and dense cloudof considerable vertical extent in the form of a mountain or huge tower, often associated with heavy precipitation, lightning, and thunder. 
• More commonly known as thunderclouds, cumulonimbus is the only cloud type that can produce hail, thunder and lightning.
• The base of the cloud is often flat, with a very dark wall-like feature hanging underneath, and may only lie a few hundred feet above the Earth's surface.
• The vertical extent of Cumulonimbus ranges from 3 km to rarely more than 15 km (10 000 – 50 000 ft).
• Cb forms when three conditions are met:
  • There must be a deep layer of unstable air.
  • The air must be warm and moist.
  • A trigger mechanism must cause the warm, moist air to rise:
    • Heating of the layer of air close to the surface.
    • Rising ground forcing the air upwards (orographic uplift).
    • A front forcing the air upwards.

About Pyrocumulonimbus Clouds:

• They are thunderclouds created by intense heat from the Earth’s surface.
• They are formed similarly to cumulonimbus clouds, but the intense heat that results in the vigorous updraft comes from fire, either large wildfires or volcanic eruptions.
• So it is, for this reason, the prefix ‘pyro’ is used – meaning fire in Greek.
• They look much darker than typical clouds because of their large amounts of smoke and ash.
• Pyrocumulonimbus clouds are thought to be responsible for several aerosol pollutants (such as smoke and ash) trapped in the stratosphere and upper atmosphere. 
• And sometimes, lightning strikes generated from them even can ignite additional fires.