In 1982, I dropped out of the workforce, took a bicycle with 40 lbs. of pack, and went to Europe for what turned out to be three years. During the second summer, I was traveling eastward from a town called Angoulême, outside Bordeaux in west central France. That route took me through the Massif Central, which, although it may sound massive, is in fact a group of smallish mountains in the middle of the country. All day, I had been climbing slowly up a ridge to a high plateau in the sunlight, which was bright, but at that altitude, not too hot. In the valleys, though, the heat was building.

At the edge of that plateau, I looked down into a valley on the other side. It had been clear up until then, but what I saw impinging on the nearly cloudless day was an enormous thunderstorm, just a wall of grey with clouds rising up to the sky, moving slowly up the valley from the far end like an invading army. Looking over the edge again, I noticed that the road took just two turns leading down from my upland perch: one to descend the canyon heading up-valley, away from the storm, to a little bridge that crossed the river, and another to come back down-valley toward the storm and a cluster of buildings, tents, and vehicles that I was able to identify as the campground where I planned to spend the night. The storm had yet to reach the campground.