Pyrocumulonimbus clouds complicate firefighting operations
Members of the media may directly contact the following experts:
Patricia DeRepentigny (English and French)
Assistant Professor, Department of Geography, Environment and Geomatics, Faculty of Arts
Professor DeRepentigny is an expert in atmospheric and oceanic sciences. Her research includes climate processes, aerosols, and specifically the role of biomass-burning aerosols in the climate system.
“We often think of fires as sources of heat and energy, but any time a cloud forms in the atmosphere, that releases a lot of energy as well. When these two systems start interacting with each other, it can create a positive feedback loop in which the fire strengthens the storm and the storm creates powerful, erratic winds and lightning that can make the fire even more extreme. These kinds of destructive fire-storm interactions are becoming part of the new reality of a warming climate, making wildfires increasingly difficult and dangerous to fight.”
José Morán(English and French)
Assistant Professor, Department of Mechanical Engineering, Faculty of Engineering
Professor Morán is specialized in flame-made particles including soot. He can comment about the combustion-generated particles in fire clouds.
“Among all fire emissions, soot (nanometer-sized particles responsible for the yellow light of candles and the one you see coming out as smoke when you shake the candle or deposit if you introduce a knife on it) ranks as one of the most prominent and its influence on the atmosphere has been demonstrated in different studies. For instance, it can have a significant influence on the formation of clouds as particles act as condensation nuclei. The same phenomenon is the one explaining the so-called contrails we see when we observe a plane over the sky being particularly challenging near airport areas. Therefore, the fact that combustion emissions can produce abrupt changes in the atmosphere and change weather conditions is not surprising. However, the particular case of the so-called fire clouds or pyrocumulonimbus clouds is a complex phenomenon and may be determined by the interplay between the local geographical properties, weather conditions, material burnt (composition, relative humidity), particulate and gas emissions, and combustion conditions.”