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Re: Lightning Safety Actions

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avatar Lightning Safety Actions
May 24, 2009 09:38AM
Recent mention of Shattered Air by Robert Madgic and the discussion of Half Dome got me thinking about what to do during lightning storms in the Sierra since you should not be in the open or under trees or within a shelter (Mt Whitney, Half Dome incidents) and should not be wet (although the storms usually result in precitipation).

I took away the following conclusions:

1. The main lesson appears to be to avoid being in the highest place or near the highest place/thing
2. Know 30/30 rule (take action if 30 seconds between flash and sound indicating within 10 miles and wait 30 minutes after storm passes) even if blue sky ( "bolt out of the blue" ) as clouds may be hidden by the terrain.
3. Try to find lowest local place, possibly a ditch or depression, and insulate between ground and body
4. Shelter by tree may be reasonble but should not be near the highest tree in the area and you should not be right next to the tree
5. Cell phone use is an uncertain risk factor
6. Avoid old sheds especially those with metal roofs without appropiate lightning grounding.
7. Movement during storm appears ill advised.


(from NOAA website)

Some useful information noted below:



http://books.google.com/books?id=-BeZVUh0LQ0C see page 152


NOAA safety posters say lightning can strike 10 miles away from a thunderstorm. Is this true?
Yes, it is true. Lightning that strikes away from a thunderstorm are often called "bolts from the blue." Lightning has its own agenda. It is random and unpredictable, and defies our attempts to fit it into a convenient box to describe its behavior. We don't really know why it sometimes connects with the ground and not a tree, or a beach instead of the water. Check out these photos:



shows a radar section with lightning data overlayed (white dots). See the white dots extending out from the core of the storm to the right – about 17km away from the back of the storm?
A helmeted bicyclist experienced a lightning strike to the head under fair weather conditions with a cloudless sky. It was determined that the bolt probably originated in a thunderstorm that was about 16km away and obscured by mountains.
Lightning strikes the ground approximately 25 million times each year in the U.S. According to the NWS, the chance of an individual in the U.S. being killed or injured during a given year is one in 240,000. Assuming an average life span of 80 years, a person's odds over their lifetime becomes one in 3000. Assuming the average person has ten family members and others with whom they are close, then the chances are one in 300 that a lightning strike will closely affect a person during their lifetime.


page 648
Lightning: Physics and Effects
By Vladimir A. Rakov, Martin A. Uman
Edition: illustrated
Published by Cambridge University Press, 2007
ISBN 0521035414, 9780521035415

Check out recommendations page 648,


The cure for a fallacious argument is a better argument, not the suppression of ideas.
-- Carl Sagan

Edited 2 time(s). Last edit at 05/24/2009 10:37AM by Frank Furter.
Re: Lightning Safety Actions
October 16, 2011 09:24PM
Shattered Air is a great book. Just re-read today at the library. You feel as if you were there on Half Dome. Not sure how I would've reacted under those circumstances.
avatar Re: Lightning Safety Actions
October 17, 2011 12:12AM
Shattered Air is a great book. Just re-read today at the library. You feel as if you were there on Half Dome. Not sure how I would've reacted under those circumstances.

avatar Re: Lightning Safety Actions
October 16, 2011 09:59PM
Here's another useful document:
NOLS Backcountry Lightning Safety Guidelines
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