Lightning, a powerful natural phenomenon, can strike the ground, posing risks to structures and individuals. While homes offer considerable protection, they are not entirely immune to a lightning strike. This article explores how lightning can affect a house and its occupants.
How Lightning Enters a House
While a house provides significant shelter during a lightning storm, it is not impervious to a direct strike or the effects of nearby lightning. Lightning seeks the path of least resistance to the ground, and homes are filled with conductive materials. It can enter a structure through electrical wiring, plumbing systems, telephone lines, and internet cables. Direct strikes to external features like the roof or chimney can also allow lightning to enter, traveling through internal conductors. Additionally, lightning can strike the ground near a house and spread through the earth, potentially entering via the foundation or metal components in concrete.
The Dangers Within: How Lightning Can Harm You Indoors
Despite being inside a house, a person can still be injured or, in rare cases, killed by lightning. About one-third of lightning-strike injuries occur indoors. These injuries can result from direct contact with electrified objects, side flashes, ground current, concussive forces, and fire.
Electrocution can occur, though uncommon, if lightning travels through an object a person is touching, such as a wired phone or a metal faucet. These contact injuries can range from burns to cardiac arrest and neurological damage.
A more frequent cause of indoor lightning casualties is a side flash. This occurs when lightning jumps from an electrical or plumbing system to a person nearby or touching another conductor. For instance, lightning might travel through electrical lines and then jump to water pipes, potentially reaching someone in contact with them.
Lightning striking the ground outside a house can also pose a threat through ground current. The electrical charge spreads radially, and if a person is in its path, it can enter the house through the foundation or pipes, causing injury. The explosive shockwave created by lightning can also cause blunt trauma or secondary injuries from falling debris if structural elements like walls or glass are shattered.
Fire is a significant secondary danger, as lightning can ignite flammable materials within the house. The intense heat of a lightning bolt, which can reach temperatures of up to 50,000°F, can instantly ignite wood and other building materials. Fires often start in the attic or roof but can also be caused by electrical currents overheating or vaporizing wires, potentially leading to fires hours after the initial strike.
Staying Safe During a Lightning Storm
To minimize risks indoors during a lightning storm, avoid contact with water. This means refraining from showering, bathing, washing dishes, or using any plumbing, as lightning can travel through a building’s water pipes.
Stay away from windows and doors. Unplug sensitive electronics and appliances before the storm arrives. While surge protectors offer some defense against common power surges, they do not provide complete protection against a direct lightning strike; unplugging offers the best defense. Cordless and cell phones are safe to use during a storm, provided they are not connected to an outlet via a charger.
Avoid lying on concrete floors or leaning against concrete walls, as these can contain metal rebar or other conductive materials that might carry a current. Wait at least 30 minutes after the last clap of thunder before resuming normal activities or venturing outside. This waiting period ensures the storm has moved a safe distance away.