It also explains their being in rather good shape.
I initially looked at this and went damn, these people are fit and muscular, quite low body fat for midwesterners... and near a tornado, just at the threshold between the 'we can safely run away' and 'we are fucked' distance from a tornado... yep, probably storm chasers.
Huh. Thank you for providing proof, between his big feet, the car's side-headlights, and her left index finger being short, I really thought this was AI.