Assessing the Influence of Fire Weather and Continuing Currents Detected From Space in Lightning-Induced Fire Ignition

Abstract

Summer thunderstorms are important precursors of wildfires in the United States, accounting for a significant portion of the total burned area. Wildfire forecast systems can benefit from investigating the preferential meteorological conditions, cloud-to-ground lightning characteristics, and fire danger indices of lightning-induced wildfires. In this study, we investigate the meteorological conditions during the occurrence of fire-igniting strokes, the value of fire danger indices, the presence of continuing currents detected from space, and the polarity of the strokes. Previous studies have independently investigated lightning candidates reported by lightning location systems or space-based instruments; however, we integrated data from both sources in our analysis. We found that the cloud-to-ground lightning ignition efficiency of fire-igniting strokes with continuing current is slightly higher than that of cloud-to-ground lightning without continuing current. In particular, we report that strokes with continuing currents lasting more than 10 ms may have a higher potential to produce wildfires than cloud-to-ground strokes without continuing currents when the conditions for the initial spread of the fire are less favorable. Our results suggest that the polarity of the strokes does not significantly influence the likelihood of a fire.