Correlation of Lightning Location Network Data with Internet-Collected Ball Lightning Case Studies

Most of the extant data concerning ball lightning is in the form of eyewitness accounts unaccompanied by any objective physical data such as photographs or instrumentation readings. In June of 2020, we established a website to collect eyewitness reports of ball lightning with the intention of correlating suitable reports with lightning location network (LLN) data and other objective meteorological information. As of July 2022, we had received over 500 submissions to our website. While many of the reports concern incidents that are too far in the past to be correlated with historical LLN data, about 20% were reported to occur in 2010 or later, and some of these were reported within only days of the incident in question.

Using reports whose time and location data were precise enough to allow meaningful correlation with LLN cloud-to-ground (CG) stroke data from Earth Networks, we have selected seven cases which show good correlation between the description of the ball-lightning incident and accompanying weather conditions by the eyewitness on the one hand, and CG stroke data in the time and space vicinity of the incident as indicated by LLN data on the other hand.

One important unresolved question about ball lightning is whether it requires a CG stroke in close proximity (a few hundred meters or less) to form. Some theories of ball lightning require this while others do not. Of the seven cases we studied, the closest identifiable CG stroke in the appropriate time frame was within 1 km for two cases, and between 1 km and 2.8 km in the other five cases. In four of the cases, the incident location was outside the 99% error ellipse for the stroke, and this should not occur if the hypothesis that ball lightning must be in close proximity to a CG stroke is true. These cases suggest that although ball lightning is generally associated with thunderstorm activity, it does not require a CG stroke nearby to form. While there are many eyewitness reports that agree with this conclusion, our study provides some of the first objective data to confirm it. Additional data and case studies may be presented at the conference.