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Lightning!

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by Chris Devaney

Outdoors

• If you are caught outdoors during an approaching thunderstorm, get into a metal vehicle (non-convertible, non-fiberglass).  Roll up the windows and do not touch any metallic parts.  If you are driving, use common sense and pull over if it is appropriate.  Keep in mind that if a lightning strike hits the car or just nearby, in all likelihood the bright flash will momentarily blind you making safe driving all but impossible. 

• If escape to a vehicle is not possible, your potential risk is magnified. 

• Do not go under a tree.  Lightning tends to strike tall objects.

• Do not seek shelter in a 3-corner shed or open structure like a pavilion or gazebo.  They may offer protection from the rain but not lightning.

• Avoid open areas and high ground.  Move quickly to a lower elevation and seek a low spot such as a ditch or valley.  Do not lie down, rather, minimize your ground contact.

• If you experience any of the symptoms that lightning is about to strike (see Lightning Proximity Symptoms sidebar), crouch low, keep your feet together, or better yet balance on one foot if at all possible to minimize surface contact with the ground.  Cover your ears as the thunder will be deafening.

• Stay away from water.

• If you are in a group, spread out.  Do not congregate closer than 15 feet to each other.

  

30/30 Rule

When a thunderstorm is on the roll, use the 30/30 Rule to determine the proximity of the lightning and when it is safe to move out from a safe place of refuge. 

When you see a lightning flash, count the number of seconds until you hear the associated thunder.  Since sound travels approximately 1 mile in just under 5 seconds, you should be on your way to a safe refuge when the seconds count is 30 between lightning flash and thunder clap.  That puts the distance between you and the storm at about 5 to 6 miles. 

You should remain in your safe refuge for 30 minutes after you see the last lightning flash.  Even then, stay alert for the rare but real threat of positive lightning after the cloud has moved away.

The Bottom Line 

No one is completely safe from lightning.  There are some things you can and should do to maximize your safety but the bottom line is: Lightning is a natural phenomena, highly unpredictable in behavior and potentially lethal in consequence.  Do all you can ahead of time to protect yourself, your family, the farm animals, your possessions and home.  Visit the references supplied in this article for more information.  Post emergency numbers, first aid information, and first aid kits in an accessible place.  Get a cell phone and develop a plan for dealing with fire and lightning hazards. 

Knowledge is the key to unlocking the fear within.  But in the case of lightning, my fear did not subside by researching the phenomena.  I gained an enormous respect for the degree of danger that accompanies a thunderstorm.  It’s a fact, lightning is a killer, serious business, and safety, at best, is only a gamble.  I’ve put the odds in my favor by learning about it.  Nevertheless I still have some unanswered questions to be addressed.  Perhaps these apply to you as well so I’ll list them and maybe together we can find solutions to these or other concerns and post them on our forum.

Additional Concerns 

1.          My water supply is supplied by a well.  I have plastic pipe feeding the water system from the well to the inside fiberglass water tanks.  There is a one-way valve between the above ground pump located in the house and the well which keeps the internal plumbing filled with water so as not to lose the prime on the pump.  Downstream of the one-way valve, the water drains back into the well using plastic pipe to keep it from freezing in the winter.  Thus there is an interruption of water between the pump and the well.  This means that there is not a complete electrical ground path between the well and the house and therefore I am unprotected from a direct lightning strike.

2.          I have a metal roof.  I also have 3 roof-mounted wind generators on metal poles attached to the house.  Each pole (1.5” sch 40 pipe) is grounded to a brass rod sunk into the ground adjacent to the house.  My electrical system (12 volt) is also grounded there.  Each pipe goes to ground via an 8 ga. copper wire.  Lightning produces 100,000,000 volts, 30,000 amps and enough heat to vaporize a wooden house.  What conductor could possibly withstand a direct hit and safely bring the charge to ground without igniting a fire?

If after reading this article you have some lightning related concerns, either post them on the forum if you are a member or email them to me using the contact information available by clicking on my name at the top of each page.  I will post them and direct you to an appropriate resource if at all possible.

Reference Sources 

Here are some additional references providing additional information about lightning and lightning related safety information. 

www.lightningsafety.noaa.gov

www.lightningsafety.com

www.nols.edu/resources/research/pdfs/lightningsafetyguideline.pdf

Phyllis Engelbert, The Complete Weather Resource Vol.  2, U.X.L.  an Imprint of Gale Research, 1997.

Orville, R.E.  and Huffines, G.R., 2001: Cloud-to-ground lightning in the United States: NLDN results in the first decade, 1989-1998.  Mon.  Wea.  Rev., 129, 1179-1193.

Halliday, Resnick, Walker, Fundamentals of Physics Sixth Ed., John Wiley & Sons, 2001.

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