Weak lightning in developing thunderstorms can trigger deadly wildfire
The geographical location of the case in this study. The background shows the fire scene, where heavy smoke indicates extremely violent flames. Combined with the fire source identified by local firefighters after the incident (upper right) – a lightning strike that passed through the tree vertically from top to bottom – this evidence confirms the cause of the fire. Credit: Qu Zhengyang
Forest fires caused by lightning are serious natural disasters. However, due to the regional and random nature of lightning, the scientific community still does not completely understand the characteristics of lightning that cause fires.
Through comprehensive analysis of multi-source data, researchers from the University of Science and Technology of China and the University of Information Science and Technology revealed that weaker lightning during thunderstorm development can also trigger wildfires. This discovery, recently published in the journal Atmospheric and oceanic scientific lettersis crucial for early warning of fires caused by lightning and for the formulation of disaster prevention strategies.
In this study, researchers analyzed a severe fire caused by lightning that took place in southwest China on March 30, 2019, which left 30 people dead. They integrated surface weather data (precipitation, relative humidity, wind speed) with cloud top brightness temperature data from the Himawari-8 satellite to reconstruct the detailed weather field at the time of the fire.
The analysis revealed that the inflammation occurred during the developing phase of the storm, not during the mature phase as traditionally thought. The frequency and intensity of the flashes were lower during this phase, but the discharge characteristics were unique.
Comparing with another case of lightning-triggered fire that occurred in the same region in June of the same year, the study further found that negative lightning accounted for a very high proportion of fires in both cases.
“This research potentially changes our conventional understanding of lightning ignition mechanisms,” says Professor Yong Xue, corresponding author of the study. “Although lightning during the developing phase of a thunderstorm is generally weaker than during the mature phase, it can pose a higher risk in terms of igniting combustible materials due to the distinct atmospheric conditions often present during this phase, such as light precipitation, low humidity and strong winds.”
This study not only deepens our understanding of the causes of these fires, but also provides new ideas for the prevention and control of lightning-induced wildfires in mountainous areas around the world.
More information:
Zhengyang Qu et al, On possible meteorological factors contributing to lightning-triggered wildfires in western Sichuan: a case study of the MuLi wildfires in March 2019, Atmospheric and oceanic scientific letters (2025). DOI: 10.1016/j.aosl.2025.100714
Provided by the Institute of Atmospheric Physics of the Chinese Academy of Sciences
Quote: Weak lightning during developing thunderstorms can trigger deadly wildfires (October 14, 2025) retrieved October 14, 2025 from https://phys.org/news/2025-10-weak-lightning-thunderstorms-trigger-deadly.html
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