A pyrocumulonimbus (pyroCb) is a fire-generated thunderstorm. Extreme heat from a large wildfire or volcanic eruption creates a convective column powerful enough to develop a full cumulonimbus with anvil, lightning, and precipitation. These lightning strikes can start new fires tens of kilometres away.
Atmospheric impact
PyroCbs inject smoke and aerosols into the stratosphere (12–20 km), where they can persist for months and affect regional climate. Australia's 2019–2020 megafires generated pyroCbs that injected more aerosols into the stratosphere than some moderate volcanic eruptions. The phenomenon is increasing in frequency due to climate change and intensifying fire seasons.