Analysis of Environmental Conditions Associated with Lightning-Ignited Wildfires in the Contiguous United States

In 2022, the U.S. National Interagency Fire Center reported that lightning caused 11% of all wildfires but accounted for 55% of the total burned area. These fires often ignite in remote, hard-to-access regions, complicating firefighting efforts. Factors like strong winds, dense fuel, and multiple concurrent ignitions can further accelerate fire propagation, making management challenging. Understanding the association between lightning and environmental parameters is crucial for improving fire prevention and management strategies.

In our research, we extracted environmental parameters at the locations and times of lightning strikes, as provided by the Earth Networks Total Lightning Network (ENTLN). We then formulated two distinct datasets: 1) Environmental parameters associated with lightning that started wildfires and 2) Environmental parameters associated with lightning that did not result in wildfires. We analyzed precipitation at different time scales from NOAA’s Multi-Radar Multi-Sensor (MRMS) project and multiple parameters sourced from the gridded surface meteorological dataset (GRIDMET), including fuel moisture, energy release component, near-surface humidity, and more.

Our analysis reveals statistically significant differences in all environmental conditions between fire and non-fire lightning strikes. To understand the practical impact of these parameters, we introduced effect size measurements to quantify the differences. Additionally, we segmented the data into the seven National Climate Assessment (NCA) regions to investigate regional variations in lightning-induced wildfire dynamics, highlighting how these factors differ across diverse climatic areas. For instance, we found that near-surface humidity was more influential in the western CONUS compared to the eastern CONUS, while precipitation and fuel moisture were more critical in the eastern CONUS. These findings underscore the complex interplay between environmental conditions and wildfire occurrences, highlighting the need for region-specific strategies to mitigate the increasing risk of lightning-initiated wildfires under changing climatic conditions.