Lightning Safety: When to Go Inside and What to Avoid
Hearing thunder means lightning is close enough to threaten; move to a substantial building or hard-top enclosed vehicle, avoid conductive paths indoors, and wait at least 30 minutes after the last thunder.
Timeline
- Before activity: Check the forecast and identify a substantial building or hard-top enclosed vehicle before storms develop.
- At thunder or lightning: Stop the activity and enter safe shelter immediately; no open shelter or isolated tree is safe.
- After the storm: Remain sheltered for at least 30 minutes after the last thunder before resuming outdoor activity.
Thunder is the practical warning to act. If you can hear it, lightning is close enough to strike your area, even when rain has not started or a patch of blue sky remains visible. The National Weather Service and CDC advise going indoors as soon as thunder is heard or lightning is seen rather than waiting to judge distance by counting seconds. [1][2][3]
The preferred shelter is a substantial enclosed building with wiring and plumbing, or a fully enclosed hard-top vehicle with its windows closed. A car protects occupants mainly through its conducting metal shell, not its rubber tires. Tents, picnic shelters, gazebos, dugouts, open garages, convertibles, motorcycles and golf carts do not provide the same protection. [1][2][3]
If no safe shelter is nearby, move toward one immediately. Leave ridges, peaks, open fields, beaches and water; do not stand beneath an isolated tree or beside poles and fences. No outdoor location is lightning-safe. Older advice to lie flat increases contact with ground current, so the CDC specifically says never lie flat; separating a group can reduce the number injured by one strike. [2][3]
Indoors is much safer, but lightning can enter through a direct strike, wiring, plumbing, antennas or the ground. During the storm, avoid showers, sinks and running water; do not use corded phones or equipment connected to an outlet; stay away from windows, doors, porches and concrete surfaces that may contain metal reinforcement. A mobile or cordless phone is acceptable. [2][4]
Wait at least 30 minutes after the last sound of thunder before going back outside. Storm edges are dangerous, and lightning can strike miles from the rain core. For organized events, the plan should identify who monitors weather, how an alert is communicated, where people shelter and how long evacuation takes; a delayed game is less costly than a preventable exposure. [1][2][3]
A person struck by lightning does not retain an electrical charge and is safe to touch. Call emergency services, make sure rescuers are not still exposed, and assess breathing and circulation. Lightning can cause cardiac arrest; begin CPR and use an automated external defibrillator if indicated and available, following emergency-dispatch instructions and the rescuer’s training. [2][5]
The best safety decision happens before the first rumble. Check forecasts, watch the sky, keep weather alerts enabled and choose the shelter before hiking, boating, swimming or starting a field event. At the first thunder, execute that plan. Trees and open-sided structures may keep off rain, but rain protection is not lightning protection. [1][2][3][4]
Sources
- National Weather Service — Lightning Safety
- CDC — Safety Guidelines: Lightning
- CDC — Lightning and Your Safety
- National Weather Service — Lightning Indoors
- American Red Cross — Lightning Safety