When I was in Missouri, periodically I would be out on a bike ride in the middle of nowhere, and hear the tornado sirens blasting off all around me. I never had any idea what to do, but I just kept heading down the trail and decided if I ever saw a tornado, I'd head for a ditch or open field.
When I was bike commuting, the official tornado plan for my office was to send eveyrone home should a tornado strike. I could imagine limiting the liability of the company, but the policy just never made sense to me... and I didn't want to head off-site into a tornado on my bike.
I suppose I rode in some lightening. Not too bad. But the idea of riding one's bike in golf-ball hail scared the living daylights out of me.