I'm no expert but I'd assume it has to do with sensor sensitivity. A nuclear bomb involves far more nuclear reactions than a lightning storm. It's as though you

I'm no expert but I'd assume it has to do with sensor sensitivity. A nuclear bomb involves far more nuclear reactions than a lightning storm. It's as though you calibrated a scale to measure "things that have mass" but set it to 10kg, assuming everything under was weightless. Changing those calibrations might be a physical (instead of digital) process, so maybe not.