Extreme wildfires have recently caused disastrous impacts in Australia and other regions of the world, including events with strong convective processes in their plumes (i.e., strong pyroconvection). Dangerous wildfire events such as these could potentially be influenced by anthropogenic climate change, however, there are large knowledge gaps on how these events might change in the future. The McArthur Forest Fire Danger Index (FFDI) is used to represent near-surface weather conditions and the Continuous Haines index (CH) is used here to represent lower to mid-tropospheric vertical atmospheric stability and humidity measures relevant to dangerous wildfires and pyroconvective processes. Projected changes in extreme measures of CH and FFDI are examined using a multi-method approach, including an ensemble of global climate models together with two ensembles of regional climate models. The projections show a clear trend towards more dangerous near-surface fire weather conditions for Australia based on the FFDI, as well as increased pyroconvection risk factors for some regions of southern Australia based on the CH. These results have implications for fields such as disaster risk reduction, climate adaptation, ecology, policy and planning, noting that improved knowledge on how climate change can influence extreme wildfires can help reduce future impacts of these events.

A number of devastating wildfires occurred in southeast Australia on 7 February 2009, colloquially known as Black Saturday. Atmospheric responses to this extreme fire event are investigated here with a focus on convective processes associated with fire activity (i.e., pyroconvection). We examine six different fire complexes on Black Saturday, finding three clearly distinct pyrocumulonimbus storms, the largest of which reached heights of 15 km on that day and generated hundreds of lightning strokes. The first lightning stroke was recorded near the largest fire complex 5 h after fire ignition. One of the pyrocumulonimbus storms was initiated close to midnight due to mesoscale influences, consistent with extreme fire behavior observed at that time for that particular fire. As another example of fire‐atmosphere interactions, a fire that started late on Black Saturday is examined in relation to ignition caused by pyrogenic lightning, with implications for understanding the maximum rate of spread of a wildfire. Results are discussed in relation to another pyrocumulonimbus event associated with the 2003 Canberra fires. Our findings are intended to provide a greater understanding of pyroconvection and fire‐atmosphere feedback processes, as well as help enhance wildfire response capabilities. We also demonstrate the potential for using lightning, radar, and satellite remote sensing in combination with thermodynamic analyses as well as synoptic and mesoscale dynamics to provide enhanced real‐time guidance for dangerous fire conditions associated with pyroconvection, as well as for the risk of new fire ignitions from pyrogenic lightning.

Research in the pursuit of better understanding of fire behavior and fire‐atmosphere interaction has frequently encountered a dearth of observational data, especially from events that cause most impact. Here we show that meteorological radar has been demonstrated as an effective tool for profiling the microphysics, thermodynamics, and fire behavior feedback of wildfire plumes, including for cases with deep and moist convection occurring in the fire plume. A synthesis of knowledge on the use of radar for the analysis of wildfire is presented, and the new term pyrometeor is introduced to describe the range of scatterers observed by radar, the reflectivity signature of which is determined by interacting processes of wildfire behavior and atmospheric convection. The reflectivity theories of pyrometeors are compared, and it is shown that there are gaps in knowledge on the size distributions of pyrometeors as well as the complex dielectrics. Observational case studies are compared across plume microphysics, plume thermodynamics and deep pyroconvection, and operational usage of radar to monitor wildfire. The dominant hypothesis of reflectivity is scattering from ash particles, though theories for scattering such as from larger debris exist, although evidence is limited for any hypothesis. Vortices have also been identified using Doppler velocity radar data, but there is limited understanding of their cause and influence on fire‐atmosphere interactions. Recommendations are provided for methods and data sets to advance the application of radar for observing and understanding wildfires, including for plume microphysics and atmosphere‐fire interactions.

23The process of pyroconvection occurs when fire-released heat, moisture and/or

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