Can Soil Swell From Lightning?

Lightning Facts

• When positive and negative electrical charges form inside thunderclouds, sparks jump between them. Roughly 100 of these bolts hit the earth every second, and each can carry up to a billion volts of electrical energy. Each segment of a lightning bolt is about 150 feet long and is produced by the negative energy that gathers at the bottom of storm clouds. When it passes close to an object on the earth, such as a building or a tree, it creates a streamer, or a surge of positive electricity that moves upward, creating a visible bolt of lighting. Some types of lightning stay in the clouds, traveling inside them or moving between them. The air surrounding a lightning bolt can get five times hotter than the surface of the sun, a temperature that can alter the shape and properties of soil particles, causing them to swell and fuse together.

Soil Components

• All soils found on earth are composed of varying amounts of sand, clay, silt and humus, or decayed vegetative matter. Soils that are high in sand also contain high levels of silica, a shiny glassy substance most often known as quartz. Depending upon its location on the earth and what stage it is at in its formation, soil can contain higher levels of some substances than others. Composed of tiny particles of worn-down rocks, sand is particularly susceptible to changes brought about when lightning strikes it. Soils with a high sand content can literally be melted by the extremely high temperatures created by a single bolt of lightning.

Fulgerites

• Fulgerites are formed when the moisture and air in the soil are quickly heated enough to explode. This expansion process forms a tubular space not unlike that found in some sea shells. As the sand melts, it is pushed outward to form a shell around this space that solidifies as it continues to cool. The often oddly-shaped objects are sometimes a combination of fused sand crystals attached to a rock that happened to be nearby when the lightning struck. In other cases, fulgerites assume a shape that mimics the path the lightning bolt took through the soil. They are found most often by unsuspecting individuals who have no idea what they are seeing. Made of true glass and impervious to weathering, fulgerites can exist for thousands of years.

Considerations

• Also called petrified lightning, the delicate fulgerites range in size from 1/4 inch to 3 inches, often have paper-thin walls, and their color varies based on the type of sand from which they were made. If found in the sand, they can be tan, gray or black, and nearly translucent white specimens have been found on some Florida beaches. Fulgerites are also found on rocks, in which case they appear as a thin glassy crust or tiny holes lined with glass.