Rocky Mountain Chapter - Colorado

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Lightning Precautions for Hikers
Submitted by Sierra Club member Frank R. Leslie

Introduction

Disclaimer:  There are no guarantees with lightning, as unpredictable effects may occur.  Travel at your own risk.

Trail crews often work in alpine areas (open grassy meadows) well above the treeline.  In these open meadows, workers are at risk from lightning strikes.

In high mountain passes, there is little shelter, and the best precaution is the rapid descent to a lower, heavily treed forest.  Within a heavily forested area, there are many trees that spread the risk of a lightning strike near you.

Dodging Lightning Dangers

I recommend a position crouching with your feet next to each other and your arms wrapped around your legs.  Avoid contact between hands and ground.  In forested areas, stay at least 8 ft away from the trunk of an average height tree.  Do not stand near a tall tree that projects above its companions.

After lightning current flows down a tree, it dissipates through the roots and wet soil.  This current is closer to the surface if the soil is dry except in the top rain-soaked area.  In these conditions, the current flow is concentrated in perhaps the top six inches of soil.  As if flows away from the tree, there is a voltage drop across the wet soil.  Cattle and horses are especially likely to be shocked, as their hooves are far apart.  So by keeping our feet together, we limit the voltage dirfference that might cause current to flow up one foot and down the other.  The risk of taking a strike to the head or shorulder is reduced by crouching.

Members of a party should stay separated by at least ten feet, as if one person is struck, the others will likely survive, and then provide CPR for the struck person.  This is about the only time that CPR in the wilderness is worth doing, as it is impractical to do CPR for several hours.  Lightning strike victims have a very good chance of resuscitation when they are immediately given CPR.  They are not electrically charged; after all, they are lying on the ground, and the lightning has stopped.

An obvious warning is when the electrical field strength in the air is so high that your hair stands on end.  In a memorable videotape, some three smiling hikers were standing there with their hair rising, and a moment later, two were struck and killed by lightning.  A nondestructive test of this is to put your arm near your TV screen.  You will feel the hairs being attracted to the screen.  If you should feel a similar effect on a mountain peak, it's time to run fast to lower protection.

Frequently Asked Questions

Q: How far can one hear thunder?
A: About twelve miles in quiet winds.  If a storm is moving towards you at thirty miles an hour, you have about 20 minutes to get to a safer location before it reaches you.

Q: What is the Schumann resonance? (OK, no one would ever ask this.)
A: The Schumann resonance effect exists between the Earth and clouds.  The variations in electrical field strength reflect the global variations in lightning activity.  Distant storms can be detected with sensitive receivers of these oscillations.

Links

Lightning Safety General lightning safety tips
National Lightning Safety Institute
Lightning Injury Research
Stalking Lightning

From The Sun-Powered Hiker Web Page by Frank R. Leslie

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Contacts

For more information about the Rocky Mountain Chapter's Outings program, please contact:

Outings Chair: Jacob Morgan - outings@rmc.sierraclub.org

Assistant to the Chair: Gary Matthews - gary.matthews@rmc.sierraclub.org

RMC Web Master: Charlie Oriez - Webmaster@rmc.sierraclub.org

Member of Peak to Peak Trail and Wilderness Links

Last update:
September 26, 2003