Comparing Lightning Detection Networks for Wildfire Ignition Attribution

Cloud-to-ground lightning frequently produces wildfire ignitions under favorable weather and fuel conditions. Rapidly identifying lightning-ignited wildfires helps mobilize suppression resources and ignition attribution supports forensic wildfire investigations. In the United States, two ground-based lightning detection networks support these goals: the Earth Networks Total Lightning Detection Network (ENTLN) and the Vaisala National Lightning Detection Network (NLDN). Here, we examine warm season (May-September) cloud-to-ground (CG) lightning pulse detections from both networks during 2020 by gridding point-based detections to a 50 km grid. After applying a basic quality control step of removing pulses between -10 and 10 kA, we find NLDN generally detects more pulses per cell than ENTLN in the western US; whereas at the continental scale, regional differences emerge. We include a comparison of detections within 2020 wildfire perimeters from three datasets (Monitoring Trends in Burn Severity, InFORM, and CALFIRE’s Fire and Resource Assessment Program) with a specific focus on California’s 2020 August Fire Siege, to qualitatively evaluate detection efficiency and fire growth. This investigation is supported by satellite fire detections from the Visible Infrared Imaging Radiometer Suite. Our results indicate both networks reasonably identify CG lightning near and within known wildfire perimeters, often in proximity to the heel of wildfires and the first satellite detections.