Increased outdoor activity in the summer increases our potential exposure to lightning and lightning storms. While lightning can be a dangerous and even deadly hazard, there are simple, easy steps you can take to avoid most lightning incidents.

According to The National Weather Service, lightning strikes the United States about 25 million times a year. Although most lightning occurs in the summer, strikes can happen time of year. Over the last five years, lightning kills an average of 17 people yearly in the United States, and hundreds more are severely injured.

General Lightning Safety Tips

Most lightning starts as an electrical imbalance inside a thunderstorm and travels through clouds. Lightning can stay within those clouds or travel through the air and eventually strike the ground.

There are roughly 5 to 10 times as many flashes of lightning in the clouds as on the ground, but individual storms may not always adhere to that pattern. Every year there are hundreds of lightning strike victims.

Outdoor activities, including work, should be suspended at the first sign of bad weather. The National Weather Service offers these general lightning safety tips:

• NO PLACE outside is safe when thunderstorms are in the area.
• If you hear thunder, lightning is close enough to strike you.
• When you hear thunder roar, immediately move to a safe shelter. Either a sturdy building with electricity or plumbing or an enclosed, metal-topped vehicle with the windows up.
• Stay in a safe shelter until at least 30 minutes after the last rumble of thunder.
• Stay current on your local weather forecast via a NOAA weather radio* or the local news.

* NOAA stands for the National Oceanic and Atmospheric Administration, and the National Weather Service is a division of NOAA.

Indoor Lightning Safety Tips

When it comes to indoor lightning safety, not all structures are equal.

Safe shelters are considered substantial buildings with electricity and plumbing or metal-topped vehicles with the windows closed. These are the safest places to be in a storm. Picnic shelters, open garages, and other open structures without plumbing or electricity are not safe locations.

Lighting enters structures in three main ways: a direct strike, through wires or pipes that extend outside the structure, or through the ground. Once in a structure, lightning can travel through the electrical appliances, phone lines, plumbing, and radio/television reception systems. Lightning can also travel through metal wires or bars in concrete walls or flooring.

• Stay off corded phones, computers and other electrical equipment that puts you in direct contact with electricity.
• Avoid plumbing, including sinks, baths, and faucets.
• Stay away from windows and doors, and stay off porches.
• Do not lie on concrete floors, and do not lean against concrete walls.

Outdoor Lightning Safety Tips

If you find yourself outside in deteriorating weather conditions with no safe shelter nearby, the following actions may reduce your risk:

• Immediately get off elevated areas such as hills, mountain ridges or peaks.
• Never lie flat on the ground.
• Never shelter under an isolated tree.
• Never use a cliff or rocky overhang for shelter.
• Immediately get out and away from open areas and open water like ponds, lakes and other bodies of water.
• Stay away from objects that conduct electricity (metal fences, power lines, windmills, etc.)

Best Practices for Lightning Safety at Work

1. Prevent worker exposure to lightning by having precautions in place

Storms don’t restrict themselves to occurring only during off-duty hours, so it’s crucial to have lightning safety plans in place at work. In their fact sheet on the subject, OSHA reminds employers that they should recognize lightning as an occupational hazard.

2. Don’t Get Caught Outside

A big cause of lightning deaths and injury comes from not getting inside fast enough, or resuming outdoor activities too soon after the last sound of thunder.

If signs of an approaching thunderstorm or heavy rain occur, workers should not begin any task they cannot quickly stop. Proper planning and safe practices can greatly increase lightning safety when working outdoors.

3. Seek Shelter in Substantial Buildings

Supervisors should tell workers which buildings to go to after hearing thunder or seeing lightning. The National Weather Service recommends seeking out fully enclosed buildings with electrical wiring and plumbing. Remain in the shelter for at least 30 minutes after hearing the last sound of thunder.

4. Vehicles as Shelter

Substantial buildings are the safest place to be, but if safe building structures are not accessible, employers should guide workers to hard-topped metal vehicles with the windows up. Remain in the vehicle for at least 30 minutes after hearing the last sound of thunder.

5. Phone Safety

After hearing thunder, do not use corded phones, except in an emergency. Cell phones and cordless phones are safe to use.

6. Lightning Safety Training

Employers should train all workers on lightning safety. Supervisors and workers need to know where a worksite’s safe shelters are and how long it takes to reach them.

Separating Lightning Safety Myths from Facts

Myth: Crouching down reduces your chance of getting hit by lightning if you are stuck outside in a work area, open field or golf course.

Fact: In the open, crouching does not increase your safety. Run or walk to a building or a car with a hard top. There is no viable alternative if you are too far away to reach a safe place quickly. Nowhere outside is safe for you. Always seek safe shelter.

Myth: A location is never struck by lightning twice.

Fact: Lightning strikes the same spot often, especially if it's a tall object, angular item by itself. For example, on average, the Empire State Building is struck by lightning 25 times a year.

Myth: You won't be struck by lightning if it's not raining or there aren't any clouds in the sky.

Fact: Lightning often occurs when there is no rain nor clouds. The nature of lightning is such that it can strike more than three miles from the thunderstorm's core.

Myth: By isolating you from the ground, rubber tires on a car shield you from lightning.

Fact: The metal sides and roof of most cars shield you from lightning, not the rubber tires. Vehicles with open or fiberglass-shelled exteriors, motorcycles, bicycles, golf carts and motorbikes are unsafe vehicles. When lightning strikes a car, the electrical charge enters the earth through the metal frame. When a storm is approaching, avoid leaning against doors.

Myth: People struck by lightning retain an electrical current, and you will get shocked if you touch them.

Fact: The human body does not have any electrical storage. It is safe and appropriate to give medical help to the victim of a lightning strike.

Myth: Lightning won't harm you if you're inside a house or office building.

Fact: As long as you stay away from windows and anything that conducts electricity, a house or building is a safe place to be during a thunderstorm.

Myth: Metal objects, such as jewelry, cell phones, MP3 players, watches, or other body parts, attract lightning.

Fact: The main determinants of where a lightning bolt will strike are height, a sharp shape, and isolation. Where lightning hits is entirely unaffected by the presence of metal. Mountains are stone, and lightning strikes them frequently every year.

Myth: If you're outside in severe weather, you should lay flat on the ground.

Fact: The likelihood of a fatal ground current increases while lying flat. Walk or run towards the closest secure building if you're outside during a thunderstorm.

Contact HSI

For more information about preparing your workplace for lightning, contact us today.

To download a copy of OSHA’s lightning safety fact sheet, click here.

To learn about severe weather safety, check out our Supervisor Safety Tip video on this subject.

Stay safe out there!