A wildfire in southwest France grew so powerful that its smoke column became a thunderstorm, generating lightning that struck the ground and ignited new fires beyond the original blaze, French officials said. Put another way, that means the inferno was no longer simply being propelled by the weather. It was making its own. The thundercloud also produced violent, erratic winds capable of driving the flames in new directions. The phenomenon, called a pyrocumulonimbus, or pyroCb, is rare in Europe...