Roger J. Wendell
Defending 3.8 Billion Years of Organic EvolutionSM
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Lightning Safety
Lightning Precautions for Hikers |
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"At my observation point on a sandstone monolith the sun is blazing down as intensely as ever, the air crackling with dry heat. But the storm clouds continue to spread, gradually taking over more and more of the sky, and as they approach the battle breaks out.
"Lightning streaks like gunfire through the clouds, volleys of thunder shake the air. A smell of ozone. While the clouds exchange their bolts with one another no rain falls, but now they begin bombarding the buttes and pinnacles below. Forks of lightning - illuminated nerves - join heaven and earth. "The wind is rising. For anyone with sense enough to get out of the rain now is the time to seek shelter. A lash of lightning flickers over Wilson Mesa, scorching the brush, splitting a pine tree. Northeast over the Yellowcat area rain is already sweeping down, falling not vertically but in a graceful curve, like a beaded curtain drawn lightly across the desert. Between the rain and the mountains, among the tumbled masses of vapor, floats a segment of a rainbow - sunlight divided. But where I stand the storm is only begning." Desert Solitaire, p. 136 |
Introduction
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. Lightning is the #2 killer from weather, second only from drowning, more than from hurricanes and tornadoes combined. However, only 5% of those struck die. The National loss impact is $6 billion annually. One insurance claim is filed for an average of 57 strikes. In Florida, the Nation's leading lightning state, there are two measured hot spots near Tampa and Titusville, where the lightning density exceeds 10 flashes per square kilometer per year.Lightning strikes only one victim 91% of the time, and more than one only 9% of the time. A Lightning Safety Group of the American Meteorological Society has been formed from researchers at a recent convention [In this portion of the original text Frank referenced William Roeder, a military Staff Meteorologist whose web link is no longer active... - Ed.]. In populated areas, 2.4% of lightning victims are struck while talking on a corded telephone. Think of this as a miles-long, lightning-catching antenna system that is attached to your head.
An interesting photo by Krider and Ladd (1975) shows a golf green with burns in the grass radiating from the hole flagpole. These burns are about two to four inches wide, and show travel of perhaps thirty feet before the current dissipated enough to no longer kill the grass. Near a primary lightning strike, sympathetic streamers may form, rising upwards some 30 feet but not connected with the strike. If one rises from your head ....
Lightning doesn't always strike the highest point. A photo of the Mt. Lemon strike near Tucson AZ shows a side strike to the mountain far down from the peak. I have witnessed this effect near Wind River Peak WY, where a strike bypassed a rounded 1000 foot-high peak to hit a pine tree several hundred feet down the side of the rocky slope. The tree burst into impressive yellow flame.
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. Strikes are erratic and a matter of chance.
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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.
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| Warning! Climbing, mountaineering, and backcountry skiing are dangerous and can seriously injure or kill you. By further exploring this web site you acknowledge that the information presented here may be out of date or incorrect, and you agree not to hold the author responsible for any damages, injuries, or death arising from any use of this resource. Please thoroughly investigate any mountain before attempting to climb it, and do not substitute this web site for experience, training, and recognizing your limitations! |
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