When fires cause storms

Photo Credit: Christine Harper, Department of Biodiversity, Conservation and Attractions, Australia

Fire-generated thunderstorms, sometimes called pyrocumulonimbus clouds or pyroCbs, are ferocious weather systems that are becoming more common in Australia.

The smoke from Australian fires in Victoria during the 2019/20 bushfire season reached a height of 35 kilometres. Sergey Khaykin at the Laboratory of Atmospheric Research and Satellite Observations at Sorbonne University in France reported that the smoke was so thick that it acted like a planetary shade, blocking the sun and briefly creating a cooling effect – similar to a moderate volcanic eruption.

New research-backed technology is now available that helps measure and predict fire-generated thunderstorm formation, to improve warning systems and assist fire and weather agencies with analysis and forecasting. The Pyrocumulonimbus Firepower Threshold (PFT) is a new tool based on research by the Bushfire and Natural Hazards CRC, in partnership with the Bureau of Meteorology – Australia’s national weather forecast agency.

The PFT measures the threshold or minimum firepower required for fire-generated thunderstorms to form, essentially assessing the atmospheric potential to support the development of a fire sufficiently intense enough for one of these storms to develop. The PFT is proving to be highly predictive, and it is now being used by fire agencies and land management departments, as well as by weather forecasters at the Bureau of Meteorology.

You can watch a recorded training session of the PFT that Dr Kevin Tory (Bureau of Meteorology) conducted here. You can find more information about the PFT here.