I have never been out riding when the rain made visibility zero. I have always been able to see where I was going and my lights make me quite conspicuous. I suppose if I couldn't see where I was going, I wouldn't be too comfortable riding. I don't consider lightning that big of a risk. I imagine the chances of getting hit by a vehicle are far, far greater than being struck by lightning. I have never had a tree or limb come down near me when I was riding. I have had to negotiate downed limbs and trees blocking the road, but that's when it sucks to be in a car since I can get by it and they can't. My commute entails 30 miles of riding, round trip. So if I doubled my annual commute mileage maybe I would encounter some of the situations you describe and become more wary.