What Uman and other researchers have confirmed is that lightning is composed of current spikes interspersed with long-flowing currents and is variable from strike to strike. We've seen fulgurites like soda straws. Others are one to two inches in diameter like heavy glass . Obviously, different current characteristics were involved in making different fulgurites. We've tried wet and dry earth to understand what the characteristic of the soil needs to be to make a fulgurite.
Lightning eats soil and tries to make liquids and glass.
Probably, the harder packed the earth is, the better chance you have for a fulgurite. There is also a practical reason to learn more about how and why fulgurites form. Each year, Florida averages about 10-15 lightning strikes per square kilometer, which is one of the highest rates in the nation. Underground power lines, of which there will be more as Florida's population grows, are susceptible to damage from lightning. Often only the insulation of the power line is damaged, and months will pass before the line fails from deterioration due to the chemicals in the earth.