Lightning safety outdoors

On Jul 13, 2018

INTRODUCTION

Lightning is a dangerous natural force. Information on fatalities in India as a result of lightning flashes has been extracted from a database on disastrous weather events of the India Meteorological Department (IMD). Records dating from 1979 to 2011 indicate that about 5259 persons have been killed by lightning strikes in India. The maximum number of lightning fatalities was observed in the states of Maharashtra (29%), West Bengal (12%) and Uttar Pradesh (9%). The spatial variation shows that lightning fatalities are higher over west central India. A significant number of males (89%) have been killed by lightning flashes compared to females (5%) and children (6%) in India, which is most likely due to the larger proportion of males working and moving outdoors in lonely conditions. The overall fatality rate is about 0.25 per million population per year in India. The lightning fatalities are significantly more common in the rainy and the summer seasons.

LIGHTNING

Lightning is an electrical discharge caused by imbalances between storm clouds and the ground, or within the clouds themselves. Most lightning occurs within the clouds.

“Sheet lightning” describes a distant bolt that lights up an entire cloud base. Other visible bolts may appear as bead, ribbon, or rocket lightning.

During a storm, colliding particles of rain, ice, or snow inside storm clouds increase the imbalance between storm clouds and the ground, and often negatively charge the lower reaches of storm clouds. Objects on the ground, like steeples, trees, and the Earth itself, become positively charged—creating an imbalance that nature seeks to remedy by passing current between the two charges.

Lightning is extremely hot, aflash can heat the air around it to temperatures five times hotter than the sun’s surface. This heat causes surrounding air to rapidly expand and vibrate, which creates the pealing thunder we hear a short time after seeing a lightning flash.

HOW LIGHTNING HURTS

A lightning strike in a crowded stadium is hazardous out to roughly50 feet from the strike point, with one or two fatalities and dozens of injuries. People are occasionally injured 100 feet away from a strike.This is roughly equivalent to the kill radius and injury radius of a hand grenade. The mechanisms that hurt us are the millions of volts of electricity, the heat, and the thunderous blast from the rapidly expanding air.

Ground current occurs with each strike. You can minimize your exposure to ground current by keeping your feet close together,especially avoiding lying flat on the ground. Ground current contributes to half of lightning fatalities .This is the primary mechanism where we can easily reduce lightning risks.

Side flash jumps from tall objects like trees when they are struck by ightining, so don’t seek shelter near tall trees, other tall objects, ortall vertical surfaces.

Contact is from touching long conductors like railings, cables,and fences. Conduct a web search for dead cow lightning to seemorbid images of contact and side flash.

Upward leaders emanate from high ground and tall objects when downward leaders approach the ground: even if they don’t connect with a downward leader, they can be fatal.

A direct strike usually results in cardiac arrest and/or stoppage of breathing. Direct strikes cause about 3-5 percent of lightning fatalities. Avoid high places and open ground to decrease risk of a direct strike.

The explosive force of lightning can cause blunt trauma resulting in fractures or soft tissue injuries.

Lightning-Caused Hazards

Fallen Wires: Do not touch fallen wires. Report them to the police or local utility immediately. If the wire should fall on an occupied vehicle, tell the driver to stay in it and drive away, if possible. If they are unable to drive away, tell them to wait for help and do not get out. They are safe inside the car, but should avoid touching the metal parts of the car.

Electrical Fires: If an appliance or tool catches fire, try to unplug it or turn off the current at the fuse box. Do not pour water on the fire. Use a Class C fire extinguisher or throw baking soda on the fire. If it gets out of control, call the local fire department and get out.

Worker activities at higher risk for lightning hazards include:

Logging
Explosives handling or storage
Heavy equipment operation
Roofing
Construction (e.g., scaffolding)
Building maintenance
Power utility field repair
Steel erection/telecommunications
Farming and field labor
Plumbing and pipe fitting
Lawn services/landscaping
Airport ground personnel operations
Pool and beach life guarding

Lightning Safety When Working Outdoors

There are several things one can do if caught outdoors when a lightning storm strikes. Take shelter inside a building or car and close the windows and doors. Get off farm machinery. Get out of the water if you are swimming or boating, and get away from it. If boating, stay low and avoid contact with the water.

If lightning strikes are suspected, keep clear of windows if inside a dwelling. Turn off the television and any other electrical appliances. Electricians suggest unplugging televisions and other valuable appliances because lightning can strike or cause electrical surges that can destroy these appliances. Postpone baths, showers and doing dishes until the storm passes because there is the possibility of electrocution. Stay away from water and gas pipes, electrical appliances and telephones because electricity can travel through these and cause electrocution.

If your hair stands up in a storm, it could be a bad sign that positive charges are rising through you, reaching toward the negatively charged part of the storm. That’s not a good sign! Your best bet is to get yourself immediately indoors.

If you can hear thunder, you are within 10 miles (16 kilometers) of a storm—and can be struck by lightning. Seek shelter and avoid situations in which you may be vulnerable.

Use the 30-30 rule, when visibility is good and there is nothing obstructing your view of the thunderstorm. When you see lightning, count the time until you hear thunder. If that time is 30 seconds or less, the thunderstorm is within six miles (ten kilometers) of you and is dangerous. Seek shelter immediately.

The threat of lightning continues for a much longer period than most people realize. Wait at least 30 minutes after the last clap of thunder before leaving shelter. Don’t be fooled by sunshine or blue sky!
People may also want to take certain actions well before the storm to protect property within their homes, such as electronic equipment. Surge protectors do not protect against direct lightning strikes. Unplug equipment such as computers and televisions.

If a person is struck by lightning, medical care may be needed immediately to save the person’s life. Cardiac arrest and irregularities, burns, and nerve damage are common in cases where people are struck by lightning. However, with proper treatment, including CPR if necessary, most victims survive a lightning strike,although the long-term effects on their lives and the lives of family members can be devastating.

There are three main ways lightning enters homes and buildings: a direct strike, through wires or pipes that extend outside the structure and into the ground. Regardless of the method of entrance, once in a structure, the lightning can travel through the electrical, phone, plumbing, and radio or television reception systems. Lightning can also travel through any metal wires or bars in concrete walls or flooring.

Phone use is the leading cause of indoor lightning injuries in the United States. Lightning can travel long distances in both phone and electrical wires, particularly in rural areas.

Do not lie on the concrete floor of a garage as it likely contains a wire mesh. In general, basements are a safe place to go during thunderstorms. However, avoid contact with concrete walls, which may contain metal reinforcing bars. Avoid washers and dryers, since they not only have contacts with the plumbing and electrical systems but also contain an electrical path to the outside through the dryer vent.

Avoid contact with electrical equipment or cords. If you plan to unplug any electronic equipment, do so well before the storm arrives. Avoid contact with plumbing. Do not wash your hands, do not take a shower, do not wash dishes, and do not do laundry.

MYTHS AND FACTS
Myth 1 – Lightning never strikes twice in the same place

Fact: Lightning often strikes the same place repeatedly, especially if it’s a tall, pointy, isolated object. The Empire State Building was once used as a lightning laboratory because it is hit nearly 25 times per year, and has been known to have been hit up to a dozen times during a single storm.

Myth 2 – Lightning only strikes the tallest objects.

Fact: Lightning is indiscriminate and it can find you anywhere. Lightning may hit the ground instead of a tree, cars instead of nearby telephone poles, and parking lots instead of buildings.

Myth 3 – If you’re stuck in a thunderstorm, being under a tree is better than no shelter at all.

Fact: Sheltering under a tree is just about the worst thing you can do. If lightning does hit the tree, there’s the chance that a “ground charge” will spread out from the tree in all directions. Being underneath a tree is the second leading cause of lightning casualties.

Myth 4 – If you don’t see rain or clouds, you’re safe.

Fact: Lightning often strikes more than three miles from the thunderstorm, far outside the rain or even the thunderstorm cloud. Though infrequent, “bolts from the blue” have been known to strike areas as distant as 10 miles from their thunderstorm origins, where the skies appear clear.

Myth 5 – A car’s rubber tires will protect you from lightning

Fact: True, being in a car will likely protect you. But most vehicles are actually safe because the metal roof and sides divert lightning around you—the rubber tires have little to do with keeping you safe. Convertibles, motorcycles, bikes, open shelled outdoor recreation vehicles and cars with plastic or fiberglass shells offer no lightning protection at all.

Myth 6 – If you’re outside in a storm, lie flat on the ground.

Fact: Lying flat on the ground makes you more vulnerable to electrocution, not less. Lightning generates potentially deadly electrical currents along the ground in all directions—by lying down, you’re providing more potential points on your body to hit.
Myth 7 – If you touch a lightning victim, you’ll be electrocuted.

Fact: The human body doesn’t store electricity. It is perfectly safe to touch a lightning victim to give them first aid.

Myth 8 – Wearing metal on your body attracts lightning.

Fact: The presence of metal makes very little difference in determining where lightning will strike. Height, pointy shape and isolation are the dominant factors in whether lightning will strike an object (including you). However, touching or being near metal objects, such as a fence, can be unsafe when thunderstorms are nearby. If lightning does happen to hit one area of the fence—even a long distance away—the metal can conduct the electricity and electrocute you.

Myth 9 – A house will always keep you safe from lightning.

Fact: While a house is the safest place you can be during a storm, just going inside isn’t enough. You must avoid any conducting path leading outside, such as electrical appliances, wires, TV cables, plumbing, metal doors or metal window frames. Don’t stand near a window to watch the lightning. An inside room is generally safe, but a home equipped with a professionally installed lightning protection system is the safest shelter available.

Myth 10 – Surge suppressors can protect a home against lightning.

Fact: Surge arresters and suppressors are important components of a complete lightning protection system, but can do nothing to protect a structure against a direct lightning strike. These items must be installed in conjunction with a lightning protection system to provide whole house protection.

CONCLUSION

Lightning is a deadly but often avoidable hazard. If the proper precautions are taken the threat of this hazard can be greatly reduced. Through education people can raise their awareness and understanding of lightning strikes, therefore reducing their risk of injury or death. Lightning effects everyone because it can strike anywhere and thunderstorms can move very quickly. Lighting is one of natures most concentrated ways of releasing energy which is why it can be so deadly. A person has a 1 in 3000 chance of being struck by lightning in their lifetime (National Geographic) but by being aware a person could reduce this chance significantly.

Rahul Sonkar
CES, BSc. (Marine Engg),
Dip (Industrial Safety),
PG Dip (PM & IR), GI’Fire E’

Lightning safety outdoors Rahul Sonkar