Lightning is a formidable natural phenomenon that poses an immediate and serious threat to human safety. Millions of strikes occur globally each year, and this extreme electrical discharge can cause severe injury or death. Understanding this hazard and taking swift, protective action is paramount to minimizing risk. This guide provides steps for recognizing an impending storm, finding appropriate shelter, and taking precautions both outdoors and inside a safe location.
Recognizing Danger and When to Seek Safe Shelter
The most effective protection against a lightning strike involves early detection and timely retreat to a secure location. Lightning can strike the ground more than 10 miles away from where it is raining, meaning a storm is a risk even if the sky appears blue. The thunder you hear is your direct warning that you are within striking distance.
A simple method for determining the distance of a storm is the “30/30 rule.” If the time between seeing a lightning flash and hearing the thunder is 30 seconds or less, the storm is close enough to be a serious threat, and you must seek shelter immediately. Sound travels approximately one mile every five seconds, so a 30-second count indicates the strike was about six miles away. Remain safely indoors until 30 minutes after the last sound of thunder, as over half of all lightning casualties occur before and after the storm’s peak.
A safe shelter is defined as a substantial, fully enclosed building that contains electrical wiring or plumbing, which helps safely ground an electrical charge. Another acceptable option is a fully enclosed, hard-topped metal vehicle with the windows rolled up. Structures such as open garages, picnic shelters, dugouts, or small sheds do not offer adequate protection because they lack the necessary grounding mechanisms.
Immediate Safety Measures When Caught Outdoors
When a safe building or vehicle is unattainable, immediate steps must be taken to minimize exposure in the open. The risk is not limited to a direct hit; lightning often spreads across the ground after striking, creating a deadly ground current. Avoiding tall, isolated objects is important, as a strike to a lone tree can cause a side flash that jumps to a nearby person.
You must avoid open water bodies, high ground, and metal objects such as fences, utility poles, or bleachers, which act as conductors. If you are in a group, separate immediately and move at least twenty feet apart to prevent the current from traveling between people. Dropping metal items you are carrying, like golf clubs or fishing rods, reduces your risk.
As a last resort, adopt a risk-minimizing position to reduce your profile and contact with the ground. Crouch low on the balls of your feet, placing your hands over your ears and tucking your head down. Keep your feet together to minimize the path for ground current to travel up one leg and down the other. Never lie flat on the ground, as this significantly increases your body’s contact area and exposure to ground current.
Avoiding Hazards Inside Safe Structures
Even after reaching a safe, enclosed structure, secondary hazards exist because lightning seeks a path to the ground. Lightning energy can enter a building through external connections like power lines, telephone lines, and television cables. The current can then travel through the building’s conductive materials.
A primary concern is contact with plumbing, as metal water pipes are excellent conductors of electricity. During a storm, you must avoid activities like showering, bathing, washing dishes, or using any faucet. Stay away from corded phones and avoid touching electrical equipment, including computers and appliances, because the wiring can carry a surge.
Avoid standing near windows and doors, which may contain metal components that conduct electricity. Do not lie on concrete floors or lean against concrete walls, particularly in basements or garages. Concrete often contains metal rebar or wire mesh that can carry a charge. Remaining in the center of a room, away from these conductive paths, offers the best protection.