Lightning striking water creates a significant hazard, especially for swimmers. Understanding how this immense electrical energy behaves is crucial. This phenomenon clarifies the substantial risk of being in water during a thunderstorm and outlines safety measures.
How Lightning Interacts with Water
Freshwater, like that in lakes, isn’t a perfect conductor but allows current to flow. When lightning hits, its charge primarily spreads across the surface rather than deeply, energizing a large area around the strike point.
Current spreads widely on the surface but dissipates rapidly with depth. A few feet below the surface, the electrical charge significantly weakens. However, the immediate surface area can still carry dangerous electrical potential.
This creates a voltage gradient. A voltage gradient is the difference in electrical potential over a distance, meaning nearby water can have varying charges. This difference drives current through anything spanning that distance, including a swimmer’s body.
The Dangers to Swimmers
The voltage gradient from a lightning strike in water directly threatens anyone immersed. When a swimmer’s body bridges areas with different electrical potentials, current flows through them. This flow disrupts the body’s natural electrical systems, controlling vital functions.
Electric shock from lightning can have severe physiological effects. It can immediately interrupt heart rhythm, leading to cardiac arrest, and affect the respiratory system, causing breathing to stop. Neurological damage is also a risk, as current can impact the brain and nervous system, potentially leading to long-term issues.
Beyond direct electrical trauma, secondary dangers exist. Muscle paralysis can incapacitate a swimmer, making them unable to keep their head above water, which quickly leads to drowning. Severe burns can occur at current entry and exit points. The dangerous radius around a lightning strike in water can extend for tens of feet, meaning even some distance from the strike point does not guarantee safety.
Preventing a Strike
Preventing lightning exposure near water begins with proactive weather monitoring. Before heading to a lake, check the thunderstorm forecast. If thunderstorms are predicted, postpone water activities.
Outdoors, heed early storm warnings. The general rule for lightning safety is “When thunder roars, go indoors.” If you hear thunder, lightning is close enough to strike, even if the sky is clear or rain hasn’t started.
Upon hearing thunder or seeing lightning, immediately exit the water and move away from shorelines, docks, and open areas. The safest location is a substantial building with plumbing and wiring, which conducts electricity safely to the ground. Hard-topped vehicles with closed windows also offer good protection. Avoid isolated trees, open shelters, or small structures, as these do not provide adequate protection.
Responding to a Lightning Incident
If someone is struck by lightning near water, immediate action is necessary. First, call emergency medical services immediately. Lightning strike victims do not retain an electrical charge and are safe to touch; rescuers are not at risk of electrocution.
After ensuring the scene is safe, assess the victim’s condition. Check for consciousness, breathing, and a pulse. If the person is not breathing or has no pulse, and you are trained, begin cardiopulmonary resuscitation (CPR) immediately.
If safe, move the victim to a secure location away from water and potential continued lightning exposure. Prompt medical attention, including CPR if needed, can improve the outcome for a lightning strike victim.