When a sudden storm rolls in, the immediate question on everyone's mind is often whether it is safe to be outside during lightning. The answer is a resounding no, and understanding why requires looking at the immense power and unpredictable nature of a lightning strike.
Lightning is not just a dramatic flash of light; it is a massive electrical discharge that can travel for miles and pack hundreds of millions of volts of electricity. Because it seeks the path of least resistance to discharge into the ground, objects and people standing on the surface become vulnerable targets. Simply being outside places you in the primary zone of risk, as your body can act as a conduit for the electrical current.
Understanding the Mechanics of a Strike
The danger of being outdoors is compounded by the mechanics of how lightning behaves. A single bolt can heat the air around it to five times the temperature of the surface of the sun, causing the rapid expansion of air that results in the thunder we hear.
Because thunder is the sound of the air expanding instantaneously, if you hear thunder, you are close enough to be struck by lightning. This rule is the cornerstone of outdoor safety, as lightning can strike ahead of, behind, or even directly within the core of a thunderstorm, often appearing on a seemingly clear horizon.
Common Outdoor Hazards
Specific environments and objects significantly amplify the risk for those outside during a storm. Open fields, hilltops, and rocky outcrops act as natural lightning rods, making these locations particularly deadly.
- Isolated trees and poles
- Metal fences and bleachers
- Water bodies like lakes, pools, and beaches
Water is an excellent conductor of electricity, and because it spreads out across the surface, a person swimming or boating can be electrocuted by side flashes or ground current traveling through the water and into their body.
Immediate Dangers and Injuries
Surviving a lightning strike is often just as dangerous as the strike itself, as the effects can be both immediate and long-term. Direct strikes are less common than ground current or side flashes, but they frequently result in cardiac arrest or severe burns.
However, a significant number of injuries come from the secondary effects, such as being thrown violently by the explosive force of the strike or being hit by debris from whatever the lightning hit. Survivors frequently report lifelong issues with nerve damage, chronic pain, and cognitive difficulties, even if they appear outwardly unscathed.
The Safe Alternative: Sheltering In Place
Because the outdoors offers no safe refuge, the best course of action when thunder roars is to go indoors immediately. A safe building is defined as one with plumbing and wiring that can provide a path for the electrical current to travel into the ground safely.
Once inside, it is wise to stay away from concrete floors, walls, and electrical appliances, as lightning current can travel through these conductive materials. The goal is to remain inside until the storm has fully passed, which is generally advised for 30 minutes after the last sound of thunder.
When Buildings Are Not Available
In rare scenarios where a person is caught outside with no building in sight, there are last-resort actions to slightly reduce risk, though they do not guarantee safety. The goal is to minimize your contact with the ground and reduce your height relative to the surrounding landscape.
| Do | Don't |
|---|---|
| Seek a low area like a valley or ravine. | Lie flat on the ground. |
| Crouch down on the balls of your feet. | Take shelter under a lone tree. |
| Keep your feet together to minimize current flow. | Climb hills or ridges. |
These measures are intended only as a final attempt to avoid a direct hit and should never replace the priority of reaching a substantial structure.
