Lightning:
Phenomenon, Risks, Prevention and Detection

What is lightning ?

Huge clouds called cumulonimbus develop during thunderstorms. These clouds get electrified due to particles colliding in internal strong draughts ; cumulonimbus become “huge batteries”. When the electrical field is strong enough, lightning can strike.
Lightning strokes occur inside a cloud or between two clouds (intra- or inter-cloud discharge) and between a cumulonimbus and the ground (cloud-to-ground). A lightning stroke can be a positive or a negative electrical discharge.
Several strokes can follow all or part of the same path in the atmosphere at close interval. They are part of the same flash.

What does lightning?

Cloud-to-ground lightning can be most disturbing and destructive for human activity.

• Direct stroke: a direct electrical discharge and the induced high heat can kill, hurt, destroy, burn or cause heavy damages.
• Conduction: lightning can strike electrical or telecommunications networks or pipes and follow the path to facilities or houses where they can hurt people, damage equipments, buildings, appliances, interrupt industrial processes, start fires,…
• Induction: the electromagnetic radiation induced by lightning can reach a nearby electrical line or conductor and induce high tension there, which then follow the line and cause damages.
• Step tension: lightning strike the earth, inducing tension in the earth, which if close by, can hurt people and animals, or damage equipments via the earthing.

How to deal with lightning threat?

Many lightning induced damages and problems can be avoided by protection and prevention, saving much time and money, and sometimes lives. When thunderstorms and lightning are forecasted or threatening

• avoid and postpone dangerous activities,
• stop ongoing dangerous activities and apply relevant safety measures
• avoid outdoor activities and call back inside any people working, playing or staying in the open air
• stop sensitive equipments, or disconnect them from the main power supply and switch to your own generator, for as long as necessary
• put on alert your maintenance crews to be ready to check and operate when the threat is over
• change your activity plans ; possibly re-route communications or vehicles to avoid thunderstorm areas
• etc…

How to detect lightning?

Watch for lightning, alarm and follow up on the threat are necessary to prevent problems caused by lightning. This can be achieved with information from a real time lightning detection network.
Meteorage and its partner Siemens have settled lightning detection sensors to detect lightning in real time over the British Isles.
The sensors continuously scan and recognise the electromagnetic waves associated with lightning and send the information in real time to the network operational centre. The information is computed there in real time to precisely locate the strokes and determine the amplitude and sign of the discharges. These information are then made available to customers via real time and past time services.