Can Lightning Strike a Lake & Kill the Fish?

How Lightning Works

• When a storm cloud forms its powerful negative charge, a stepped leader descends from the cloud. This leader is invisible and composed of zig-zagged steps. Each step is approximately 150 feet long. When the tip of the stepped leader gets within 150 feet of a positive electrical charge on the ground, an electrical channel is formed. The object sends a current up through the leader, and the cloud replies with a return stroke: the bright, hot bolt we know as lightning.

Effects of Lightning

• A lightning bolt hundreds of feet long can strike in under a second. When lightning strikes, the air around it is heated to a temperature five times hotter than the temperature on the sun. The nearby air vibrates and expands, producing the booming sound of thunder. Since sound travels more slowly than light, thunder is heard on the ground after lightning has already struck. In the case of fish, a larger fish will absorb more electricity than a smaller one if lightning hits the lake.

Fish and Lightning

• If a fish absorbs a fatal amount of electricity, death occurs immediately. However, the reason most fish in a lake are not killed when lightning strikes is that the current travels in all directions when it hits the water's surface. This has the effect of neutralizing most of the electricity for the fish below the surface. One notable exception took place in Marietta, Georgia. The lightning strike stirred up algae at the bottom of the lake, which suffocated hundreds of fish.

Electrical Experiment on Fish

• The Minnesota Department of Natural Resources performed an experiment in which officials used a generator to release electrical current into Minnesota's lakes to test the effects of lightning on fish. Nearby fish were immobilized by the electricity, and scientists were able to collect them. However, the fish quickly recovered. No fish kills in Minnesota lakes have been linked to lightning strikes. The Michigan Department of Natural Resources, however, has recorded fish kills as a result of lightning.