Pyrocumulonimbus Cloud:
The wildfires currently raging in the United States and Canada are so intense that they have created ‘pyrocumulonimbus’ clouds, which have the potential to spit out thunder and spark more fires.
- Pyrocumulonimbus clouds occur only when there is an extremely hot wildfire — volcanic eruptions can also lead to the formation of pyrocumulonimbus clouds.
- The intense heat from the fire warms the surrounding air which moves upward into the atmosphere.
- As this hot and very buoyant air — carrying water vapour, smoke, and ash — rises, it expands and cools down. Once it is cool enough, water vapour condenses on ash, forming a grey or brown cloud.
- At this stage, the cloud is known as a pyrocumulus cloud, also known as a ‘fire cloud’.
- If there is sufficient water vapour available and the upward movement of hot air intensifies, pyrocumulus clouds can evolve into a pyrocumulonimbus cloud.
- These clouds can reach heights of 50,000 feet and generate their own systems of thunderstorms.
- Although pyrocumulonimbus clouds can produce lighting, they do not generate much rain.
- As a result, they can spark new wildfires many kilometres away from the main blaze.
- These clouds can also trigger strong winds that can make the spread of the wildfire faster and unpredictable.
- Scientists believe that climate change could have a role to play in the increase of their frequency.
- Studies have shown that with temperatures soaring across the world, wildfires are becoming more common and intense.
