My best guess would be splash from the lightning strike. Same end effect as EMP, a large voltage drop over distance. It's the reason that cattle, with their front and rear hooves so far apart, do so poorly in lightning storms.
If your not using shielded cables and electronics enclosures, a near strike would fry anything in the immediate vicinity.
Hope for the best and prepare for the worst.
The object in life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane