Tuesday, June 14, 2011

Lightning Safety

Today work sent around an email on the topic of lightning safety.  It was a fascinating article so I thought I'd share it with everyone.  We've always been concerned with getting struck by lightning but less than 5% of lightning deaths are caused by direct strikes.  Ground current, side flashes, and touching something that is charged cause 85% of fatalities. 

Lightning strikes fast, usually in just a few milliseconds, so you can't escape once it is in process.  If you are in a thunderstorm the safest thing to do is to get into a building.  Unfortunately, it's not always possible.  If you are near a car or truck get into that.  If you are not near either then you may be in trouble!  Here are some things that you can do to minimize your risk when working in areas prone to lightning. 

If possible you should move indoors.  I love to stand on my back patio to watch the lightning show.  I thought I'd be ok because I wasn't out in the open.  What I didn't realize was if the patio cover was hit, instead of the lightning stopping there it would continue towards the ground, using me to conduct the current.  You see, the lightning will travel down a vertical surface to get to the ground.  When there is a gap that the lightning needs to jump, any object, including a person would bridge that gap to help conduct the current to the ground. 

Check the forecasted weather before you start your day.  Know what the local weather patterns are and work around them.  For example, if you know that the thunderstorms hit at noon be done with your outside activity before then.  Pay attention to the weather.  If you are working with others, have one person's main responsibility to be the weather.  In my line of work we have lookouts.  Their entire job is to keep everyone else safe.  They pay attention to the surroundings. 

As soon as you hear any thunder you need to get yourself immediately off exposed ground by moving to safer ground.  Get into a ravine or depression - but also be aware of flash flooding.  Avoid peaks, ridges, and higher terrain.  Avoid open spaces.  Avoid tall trees and other objects and even bushes if they are in the middle of an open area.  If the storm is coming towards a hill or mountain your best bet is on the opposite side that the storm will initially hit.  Get as far down the mountain as you can since lightning is more likely to strike at higher elevations. 

When you've blown it and you can't get to safety you will need to get into what is known as the lightning position.  Put your feet together.  This will significantly reduce the effects of ground current, the leading cause (almost half) of lightning fatalities.  Crouch to try to reduce the effect of side flash and upward leaders which together cause almost the rest of the lightning fatalities.  Wrap your arms around your legs and close your eyes.  If you have anything with you that can insulate you from the ground sit on them.  This can include a jacket, foam pad, or anything else.  Don't sit on a backpack with a metal frame!  Don't touch any metal.  Take off your rings and other jewelry. 

When the lightning hits the ground the current spreads and dissipates as it spreads.  If you are in that dissipation area, this causes a problem when one part of your body has one voltage and another part has a different voltage.  If there is a difference in voltage then this will push the electric current through you.  That's why you try to keep your feet as close together as possible. 

Side flash is when the lightning hits something tall, such as a tree, and on the way down to the ground a portion of the current shoots out the side toward something adjacent to the tall object: another tree or a person.  This is why you don't want to be around the tallest of trees or other tall objects.   

Currents will pass through long conductors such as railroad tracks, fences, corded telephones, computers, etc. and can also cause injury or death.  Fencing should have the occasional steel post to ground the fence rather than all wooden posts. 

The article that I got this information was written by John Gookin and can be found at

1 comment:

  1. Thanks. Good post and it's quite a hazard since 80% of people who receive even a glancing strike have permanent damage thereafter. This is not as rare an occurance as we would like it to be.