http://www.yumpu.com/en/document/view/4384359/ball-lightning-study-air-force-freedom-of-information-act
In particular I direct your attention to Figure 7.
http://www.yumpu.com/en/document/view/4384359/ball-lightning-study-air-force-freedom-of-information-act
In particular I direct your attention to Figure 7.