FUD. It’s not lightning.
Ground currents are interesting however they occur, and are novel to many. The remarks were correct about lightning.
The potential gradient is the thing that kills you. It can either be created by a lightning strike or by voltage induced into the ground as mentioned here.
> It can either be created by a lightning strike or by voltage induced into the ground as mentioned here.
If 'it' is lethal levels, then I don't think that 'or' is correct.
Does voltage density make any sense?
Fun fact, voltage gradient across cell membranes is typically megavolts per meter. At scale that is millivolts per nanometer, but the field strength is the same either way. Membranes are badass.