The Waroona fire burned 69 000 ha south of Perth in January 2016. There were two fatalities and 170 homes were lost. Two evening ember storms were reported and pyrocumulonimbus (pyroCb) cloud developed on consecutive days. The extreme fire behaviour did not reconcile with the near- surface conditions customarily used to assess fire danger. A case study of the fire (Peace et al. 2017) presented the hypothesis that the evening ember storms resulted from interactions between the above-surface wind fields, local topography and the fire plume. The coupled fire–atmosphere model ACCESS-Fire has been run in order to explore this hypothesis and other aspects of the fire activity, including the pyroCb development. ACCESS-Fire incorporates the numerical weather prediction model ACCESS (Australian Community Climate and Earth System Simulator, described by Puri et al. 2013) and a fire spread component. In these simulations, the Dry Eucalypt Forest Fire (Vesta) fire spread model is used. In this study we first show that the reconstruction of surface fire spread and simulated fire spread are a good match for the first day; second, we show that the model produces deep moist convection as an indicator of pyrocumulonimbus cloud and, third, we show the fire–atmosphere interactions surrounding the ember showers provided an environment conducive to the observed mass spotting. The simulation results demonstrate that ACCESS-Fire is a tool that may be used to further explore the complex processes and potential impacts surrounding pyroCb development and short-distance ember transport.

Coupled fire-atmosphere models are simulators that integrate a fire component and an atmospheric component, with the objective of capturing interactions between the fire and atmosphere. As a fire releases energy in the combustion process, the surrounding atmosphere adjusts in response to the energy fluxes; coupled fire-atmosphere (CFA) models aim to resolve the processes through which these adjustments occur. Several CFA models have been developed internationally, mostly by meteorological institutions and primarily for use as a research tool. Research studies have provided valuable insights into some of the atmospheric processes surrounding a fire. The potential to run CFA models in real time is currently limited due to the intensive computational requirements. In addition, there is a need for systematic verification to establish their accuracy and the appropriate circumstances for their use. The Bureau of Meteorology (the Bureau) is responsible for providing relevant and accurate meteorological information to Australian fire agencies to inform decisions for the protection of life and property and to support hazard management activities. The inclusion of temporally and spatially detailed meteorological fields that adjust in response to the energy released by a fire is seen as a component in developing fire prediction systems that capture some of the most impactful fire and weather behavior. The Bureau’s ten-year research and development plan includes a commitment to developing CFA models, with the objective of providing enhanced services to Australian fire agencies. This paper discusses the operational use of fire predictions and simulators, learnings from CFA models and potential future directions for the Bureau in using CFA models to support fire prediction activities.

Background: Climate projections signal longer fire seasons and an increase in the number of dangerous fire weather days for much of the world including Australia. Aims: Here we argue that heatwaves, dynamic fire–atmosphere interactions and increased fuel availability caused by drought will amplify potential fire behaviour well beyond projections based on calculations of afternoon forest fire danger derived from climate models. Methods: We review meteorological dynamics contributing to enhanced fire behaviour during heatwaves, drawing on examples of dynamical processes driving fire behaviour during the Australian Black Summer bushfires of 2019–20. Results: Key dynamical processes identified include: nocturnal low-level jets, deep, unstable planetary boundary layers and fire–atmosphere coupling. Conclusions: The future scenario we contend is long windows of multi-day fire events where overnight suppression is less effective and fire perimeters will expand continuously and aggressively over multiple days and nights. Implications: Greater overnight fire activity and multi-day events present strategic and tactical challenges for fire management agencies including having to expand resourcing for overnight work, manage personnel fatigue and revise training to identify conditions conducive to unusually active fire behaviour overnight. Effective messaging will be critical to minimise accidental fire ignition during heatwaves and to alert the community to the changing fire environment

The destructive Sir Ivan Dougherty fire burned 55,000 hectares around 250 km northwest of Sydney in New South Wales on 12 February 2017. Record hot temperatures were recorded in the area during the lead-in days and the fire conditions at the time were described as the ‘worst ever seen in NSW’. The observed weather conditions were hot, dry and very windy ahead of a synoptic frontal wind change during the afternoon. ‘Extreme’ to ‘catastrophic’ fire weather was predicted, and the potential for extreme fire behaviour was identified several days in advance. The Australian coupled fire–atmosphere model ACCESS-Fire has been run to explore the characteristics of the Sir Ivan fire. Several features resulting from fire–atmosphere interaction are produced in the simulations. Simulated heat flux along the fire perimeter shows increased intensity on the northern fire flank in response to gradual backing winds ahead of the main frontal wind change. Temporal and spatial variability in fire activity, seen as pulses in fire intensity and fireline wind speed, develop in response to boundary layer rolls in the wind fields. Deep moist convection consistent with the observed pyrocumulonimbus (pyroCb) cloud is simulated over the fire at around the time of the frontal wind change, and matches guidance from the ‘PyroCb Firepower Threshold’ tool, which showed transient favourable conditions. After the wind change, short-lived near-surface and elevated vortices suggest organised rotating features on the northern flank of the fire. The coupled model captures processes that cannot be produced in uncoupled fire predictions and that are not captured in current operational meteorological forecast products provided to Australian fire agencies. This paper links the features from coupled simulations to available observations and suggests pathways to embed the learnings in operational practice.

Fire-generated tornadic vortices (FGTVs) were observed at two high intensity fires in New South Wales during the 2019–20 ‘Black Summer’ Australian bushfires. At the Green Valley Fire, a fully laden fire truck was lifted and overturned by a confirmed FGTV, with estimated wind speeds of ~300 km h–1 (Enhanced Fujita, EF, scale rating of 3 to 4). At Wandella, impact to vehicles at the Badja Forest Fire indicates winds may have exceeded 350 km h–1 (EF5 tornado), making it one of the strongest pyrogenic winds documented globally. We use a combination of observations and insights from simulations using the coupled fire–atmosphere model ACCESS-Fire to investigate the FGTV environments. Radar and satellite observations showed both FGTVs occurred coincident with rapid acceleration of the fire’s updraft and rapid growth of pyroconvective clouds; towering pyrocumulus cloud (pyroCu) at the Green Valley FGTV and pyrocumulonimbus cloud (pyroCb) tops higher than 12 km at the Wandella FGTV. Coupled fire–atmosphere simulations resolved transient, small scale features consistent with observations, including split flow around the fire, reverse lee side inflow, fire updrafts extending to the mid-troposphere, and split fire fronts with convective towers at the head of the flanks. A likely source of vorticity for each was a zone of near ground vertical wind shear between the fire’s reverse inflow in a valley, and north-westerly winds above. The case studies contribute to growing knowledge of these destructive FGTVs, highlight the benefits of fire–atmosphere modelling, and demonstrate the operational utility of radar and satellite observations to inform warnings to communities and fire-fighting operations.

The Oceania region is characterised by strong spatial gradients in climate, terrain, ecology, and land use. Wildfire activity is correspondingly diverse, spanning frequently burning tropical savannas and less frequent but often high-impact fires in temperate regions. Here, we summarise the March 2025-February 2026 fire season across Oceania as part of the State of Wildfires project, combining satellite observations, regional datasets, and expert synthesis. The 2025-26 fire season was marked by pronounced regional contrasts. In Australia, total burned area was within the mid-range of the past two decades (477,000 km²; ranked 10th of 24 years), while the number of fires detected was the highest on record. Extensive burning occurred across tropical savanna and desert ecosystems, driven by high fuel loads following preceding wet years and extensive dry lightning ignitions. In contrast, southern Australia experienced multiple high-impact fires under extreme fire weather conditions, particularly in Victoria, where large fires caused widespread damage to homes, infrastructure, agricultural systems, and loss of life. Fire activity across eastern Australia was prolonged and spatially uneven, while in Aotearoa New Zealand, overall fire activity remained moderate but included several locally significant high-impact events. Together, these patterns demonstrate that wildfire activity across Oceania cannot be adequately characterised using single metrics such as burned area alone. The 2025-26 season highlights the importance of regionally nuanced and impact-focused approaches for understanding wildfire risk across diverse fire-prone landscapes.