# Atmospheric profiles associated with pyrocumulonimbus in southeast Australia

## TL;DR

This study examines atmospheric conditions linked to pyrocumulonimbus storms in southeast Australia, showing they form under specific weather patterns that also support wildfire spread.

## Contribution

The paper provides a statistical comparison of atmospheric profiles for pyroCb and standard wildfires in southeast Australia over 30 years.

## Key findings

- PyroCb in southeast Australia often form under hot, dry, and unstable surface conditions favorable for wildfires.
- PyroCb events are associated with steep mid-level lapse rates and diurnal moisture advection, supporting thunderstorm development.
- PyroCb and standard wildfires share similar lower-level wind profiles but differ in mid- and upper-level wind patterns.

## Abstract

Pyrocumulonimbus (pyroCb) are thunderstorms generated by wildfires. They present significant risks to first responders and civilian populations in southeast Australia and in many regions around the world. PyroCb are increasingly common in southeast Australia, with the majority of recorded events occurring in the last 20 years. We constructed, examined, and statistically compared median atmospheric profiles for pyroCb-producing and large standard (non-pyroCb-producing) wildfires in the southeast Australian mainland over a 30-year time period (1991–2020). We found that pyroCb in southeast Australia frequently develop on days with hot, relatively dry, very unstable, and moderately windy surface and low-level conditions that are favourable for wildfire spread. These conditions often occur in conjunction with steep mid-level lapse rates and significant diurnal mid-level moisture advection, resulting in conditions at least conditionally favourable for high-based thunderstorm development. PyroCb and standard wildfire events have similar wind profiles, particularly in the lower-levels, but pyroCb tend to be associated with lower winds in the mid- and upper-levels of the troposphere. However, variability within the pyroCb-related data suggests that pyroCb in southeast Australia can form in a variety of atmospheric conditions. These results may have important implications for forecasting pyroCb potential.

The online version contains supplementary material available at 10.1038/s41598-025-22530-0.