Many people wonder if umbrellas are dangerous during a lightning storm. This article clarifies the actual risks and provides guidance on how to stay safe.
The Science of Lightning
Lightning is a giant electrical discharge within the atmosphere or between the atmosphere and the ground. It begins with the separation of electrical charges within a thunderstorm cloud. Lighter ice crystals often become positively charged and rise to the top of the cloud, while heavier hail and ice particles acquire a negative charge and accumulate in the lower parts. This charge separation creates a significant electrical potential difference.
When this electrical potential becomes great enough to overcome the insulating properties of the air, a “stepped leader” of negative charge descends from the cloud towards the ground. Simultaneously, positive charges on the ground, often concentrated on taller objects, send up “streamers” to meet the descending leader. The connection of these paths completes the circuit, resulting in a visible lightning flash and the rapid heating of air to extreme temperatures, which produces thunder.
Umbrellas and Direct Strikes
Umbrellas with metal components are often mistakenly thought to “attract” lightning. However, lightning is not drawn to objects in that sense. The primary factors influencing where lightning strikes are an object’s height, its pointy shape, and its isolation in an open area. An umbrella’s metal shaft conducts electricity, but its danger during a thunderstorm stems mainly from increasing a person’s overall height.
If a person holding an umbrella becomes the tallest object in an exposed environment, such as an open field, their risk of being struck slightly increases. The umbrella doesn’t act as a magnet for lightning; rather, it makes the individual a more prominent target for the electrical discharge. While metal conducts electricity, small metal objects like an umbrella have little influence on where lightning strikes until the channel is very close to the ground.
Staying Safe During a Storm
The safest action during a thunderstorm is to seek shelter immediately upon hearing thunder. The safety rule, “When thunder roars, go indoors,” means if you can hear thunder, you are close enough to be struck. The safest place is inside a sturdy, enclosed building or a hard-topped vehicle with windows rolled up.
When inside, avoid contact with corded appliances, electrical outlets, and plumbing, as lightning can travel through these pathways. If caught outdoors with no immediate access to a safe building or vehicle, avoid open areas like fields, isolated tall objects such as trees or poles, and bodies of water. Remaining indoors for at least 30 minutes after the last sound of thunder is also recommended, as lightning can strike many miles away from the storm’s core.