What are Pyrocumulonimbus clouds, and what processes lead to their formation? Analyze the factors contributing to the increased frequency of these cloud events. (10M, 150 words) [GS-1: Climatology]

Introduction:

Pyrocumulonimbus clouds are intense thunderstorm clouds formed due to extreme heat from large-scale wildfires or volcanic eruptions.

These clouds are similar to cumulonimbus clouds but are triggered by the intense heat generated from surface fires, creating strong updrafts that lead to cloud formation.

Body:

Formation of Pyrocumulonimbus Clouds:

• Not all wildfires produce these clouds; only extreme fires with exceptionally high temperatures, such as those during the 2019-2020
• Australian bushfires, where temperatures reached 800°C, can result in pyrocumulonimbus cloud formation.
• The process starts with extreme heat, which causes air around the fire to rise, carrying water vapour, smoke, and ash. As the air rises and cools, water vapour condenses on ash particles, forming pyrocumulus or ‘fire clouds.’
• If sufficient moisture is present and the updraft intensifies, these pyrocumulus clouds can evolve into towering pyrocumulonimbus clouds, reaching heights of 50,000 feet, capable of producing thunderstorms.
• These clouds often trigger lightning but produce little rain, sometimes igniting new fires far from the original fire source. They can also generate strong winds, further exacerbating the spread and unpredictability of wildfires.

Increasing Frequency of Pyrocumulonimbus Clouds:

• The precise causes for the increase in pyrocumulonimbus events are not fully understood, as research on these clouds is still evolving. However, climate change is believed to play a significant role.
• Rising global temperatures are linked to more frequent and intense wildfires, which in turn leads to an increase in pyrocumulonimbus cloud formations.
• These clouds are also thought to contribute to the release of aerosol pollutants, such as smoke and ash, into the stratosphere, impacting air quality and the climate system.

Conclusion:

• Recent wildfires in North America, such as those in Canada and the United States, have been so severe that they are producing pyrocumulonimbus clouds, capable of generating thunderstorms and sparking new fires.
• The frequency of these clouds has increased in recent years. For example, in 2023 alone, Canada experienced 140 pyrocumulonimbus events, compared to the global average of 102 observed annually in previous years, underscoring the growing impact of climate change on such phenomena.
• Example in India: In India, rising forest fire incidents in states like Uttarakhand and Himachal Pradesh due to prolonged dry seasons and higher temperatures might trigger similar cloud formations, posing new challenges to disaster management.