Lightning

The World Meteorological Organization (WMO)’s International Meteorological Vocabulary describes lightning as an electrical discharge between a cloud and the ground. It follows an irregular but well defined and frequently forked path.
Lightning occurs during thunderstorms, and is accompanied, as the name implies, by thunderclaps as well as strong winds and sometimes hail or even tornados.

Signs that a lightning storm may be approaching

• Strong winds.
• Heavy rainfall.
• Dark clouds.

Part I – Reminders

• A large number of victims are hit by thunderstorms, but over 50% the deaths by lightning take place after the storm has apparently finished.
• It is advisable to remain indoors for at least 30 minutes after the last thunderclap.
• If there are thunderstorms nearby but not in the immediate vicinity, you may still be struck by lightning even if the sky is clear.

Advice for when there is lightning

• If a storm is approaching, stay away from high places, hill and mountain tops, open fields, isolated trees, picnic areas, grain silos, sheds and windmills. Avoid riding in convertible cars, golf-carts, and sailboats, and stay away from communications towers and power lines.
• If you are riding a solid-roof (non-convertible) car or truck, it is better to remain inside the vehicle.
• The reason you should stay away from sailboats is because masts attract lightning.
• If you can see lightning or hear thunder, you are at risk.
• If the thunder is getting louder or more frequent, the storm is approaching, increasing the risk of injuries or fatalities.
• If the time elapsed between the sight of lightning and the sound of thunder is 30 seconds or less, you are in danger.
• Large enclosed spaces are safer than small or open spaces.
• If you are indoors, do not take a shower, use the telephone or touch conductive surfaces such as metallic doors or window frames.
• In a car, keeping the windows rolled up protects you from lightning. Try not to touch the metallic parts of the vehicle.
• During a thunderstorm, do not use electrical appliances such as hair dryers, irons, television sets or electric shavers.

What to do if someone is hit by lightning?

• About 90% of people hit by lightning survive, especially if medical care is provided quickly.
• People hit by lightning do NOT carry and electric charge, so they can be handled and given medical care. Immediately after calling the doctor or an ambulance, begin mouth-to-mouth resuscitation. If the victim does not have a pulse, cardiopulmonary resuscitation (CPR) should be carried out immediately.

Part II – To bear in mind

• The air near lightning is heated to a temperature of approximately 27,000 degrees Celsius!
• A lightning strike can generate between 100 million and one billion volts of electricity.
• Every storm involves lightning; thunderstorms occur about 20 million times a year worldwide.
• Thunderstorms occur most frequently in spring and summer during the afternoon and evening, but they can occur at any time of the day or night, year-round.
• A significant number of fires are started by thunderstorms.
• Many people have died from lightning when they were sailing, swimming, playing golf, riding a bicycle, horse riding, playing football, fishing, mountain climbing or standing under a tree.

Myths and facts about thunderstorms

Myth: If it is not raining, lightning does not pose a threat.
Fact: Lightning can strike as far away as 15 Km from any rainfall.
Myth: Wearing rubber soles protects you from lightning.
Fact: Rubber soles provide no protection. Rubber tires are no help either, although it is safer to remain inside a car during a storm than going outdoors. You should try not to touch any metal surfaces, though.
Myth: People hit by lightning carry an electrical charge and should not be touched.
Fact: Lightning victims do not carry an electrical charge, and they should be cared for immediately.

What is Mr. Weather’s advice in the event of a thunderstorm?

• Stop your games or other activities.
• If you see a storm approaching, head towards a building or car.
• Stay away from trees, towers, street lights and power lines.
• If you’re swimming or sailing, head for shore.
• Practice a crouching posture for when you are outdoors and have no shelter in sight. Remember to remain on tip-toe.

Adapted from Jaquelina Michienzi, The Weather Channel
Jaquelina Michienzi was an aeronautical meteorologist at the Argentinean Air Force from 1983 to 1996. Since 1997, she has worked as a senior meteorologist at the Weather Channel.

Sources:
National Oceanic and Atmospheric Administration (NOAA), Federal Emergency Management Agency (FEMA) and American Red Cross (ARC), Thunderstorms, Tornados, Lightning.

NOAA. Avoiding the risk of deadly lightning strikes. A NOAA Backgrounder.
National Meteorological Service (SMN) of Argentina. Rayos y Tormentas. SMN Bulletin.
Argentinean Red Cross. Cuadernillo de primeros auxilios.