A person riding a bicycle can be struck by lightning, and being outdoors presents specific hazards. Lightning is an electrical discharge that seeks the path of least resistance to the ground. While the likelihood of a direct strike is statistically low, the potential for severe injury or death makes lightning safety a serious concern for any cyclist. Understanding the physics of a strike and knowing how to react can mitigate the danger when a storm approaches.
Why Cycling Increases Exposure
Cycling takes riders out of protected environments, increasing the risk of a lightning strike. A cyclist often becomes one of the tallest objects in an open landscape, especially when riding in rural areas or across flat fields. Lightning tends to strike the highest point, making the rider’s body and the bike a relative target. The mobile nature of cycling allows riders to cover large distances quickly, increasing the chance of encountering an unexpected thunderstorm front far from adequate shelter.
The time between seeing a flash of lightning and hearing the thunder, known as the “flash-to-bang” count, is the most practical way to gauge proximity. If the time is 30 seconds or less, the storm is close enough for a strike to be a direct threat, and a cyclist must immediately assume a defensive posture.
The Path of the Current
The bicycle, whether made of aluminum, steel, or carbon fiber, acts as a conductor once a strike occurs, but it does not “attract” the lightning. The strike is determined by the electric field and the height of the object. Once the charge connects, the bike’s metallic components provide a direct path for the current, often through the rider gripping the handlebars and sitting on the saddle.
A common misconception is that rubber tires offer meaningful insulation or protection from a lightning strike. Lightning has already traveled miles through the air, rendering the few inches of rubber on the tires irrelevant to the current’s path. The intense voltage will easily flash over the small insulating gap to reach the ground.
Lightning can injure a person through several mechanisms beyond a direct strike, including ground current, side flash, and conduction. Ground current is particularly dangerous when lightning hits the ground nearby, spreading outward across the surface for up to 30 meters. This voltage difference can travel up one of a person’s feet, through their body, and down the other foot, causing severe injury.
Immediate Safety Protocol
The moment thunder is heard, a cyclist should immediately stop riding and begin seeking substantial shelter. Safe locations include fully enclosed buildings with wiring and plumbing or a hard-topped, fully enclosed vehicle, which offers protection due to its metal shell acting as a Faraday cage. Trees, open shelters, and bridges should be avoided, as they offer no protection and can increase the risk of a strike or side flash.
If no sturdy shelter is readily available, the most important action is to dismount the bicycle and move away from it, as well as any other metal objects, by at least 30 meters. The rider should then seek the lowest point in the terrain, such as a ditch or depression, but avoid any area where water might collect. The safest position is to crouch low to the ground on the balls of the feet, keeping the feet together to minimize the area exposed to ground current. This low-crouch position minimizes contact with the ground, reducing the risk of a dangerous step potential shock if lightning strikes nearby. Remaining in this position until 30 minutes after the last sound of thunder is heard is the recommended safety guideline before resuming the ride.