Let's start again - is that a confirmed event of ball lightning? If so, I fully accept that currently there's no definite explanation, certainly none that could be easily explained in several sentences and there's no point in trying where scientific community has not succeeded much so many times.
On the other hand, if not, then is it just the much more common flash that happens when either wind or something else moves phase and neutral wires of very high voltage lines close enough for air in between to breakdown or very near lightning strike (presumably, but not necessarily, including ball lightning) by itself opening the near-zero resistance pathway?
If so, to the best of my understanding unintentionally connected phase and neutral without little or no load appears to be the textbook definition of a short circuit. In which case, current sharply rises, often but not always, to a damaging extent, until a breaker goes off and disrupts the circuit, any part of circuit stops functioning due to mentioned damage or limitations of the power supply cause voltage to drop below the amount that allows the arc to sustain itself.
If the latter happens (and nothing else) and this arc disappears, current and voltage return to normal, which may allow the arc to reappear nearby where circumstances are still favorable and then travel along the conductors thus forming the so called Jacob's ladder, but instead of air rising upwards by itself air presumably being moved horizontally by the wind.
And if it isn't any of that, then what is it?
Now, I am not well versed in electrical systems and physics in general, but I believe I may have at least grade school understanding or at least a will to attain such to my limited capacity. If you (or anyone) happens to be equal actual or better, please, if possible, point out my mistakes instead of brushing aside. That way you prove (rather than uselessly imply) understanding of subject and, importantly, display good forum culture. Lest I return the sentiment with much more contempt than I already did in my post above.