exterrester
i am not really sure if gravity would effect lighting or not.perhaps this has to do with wind vortexes,which maybe concentrate atmospheric ions more than other places,this might also be some sort of balance,where wind,atmosphere,geology,temperature,humidity and perhaps gravity some how are focused.i wonder if this is a transient phenomenon?by the way what is the history of this areas weather and/or lighting strikes?it is kind of curious this phenomenon isn't it?
