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[at-l] Lighting
October 19, 1999
Teach this safety slogan: "If you can see it - flee it; if you can hear
it - clear it."
Section 4.6:
LIGHTNING SAFETY FOR CAMPERS AND HIKERS
published in "The Outdoor Network", vol ix, no.2, 1998
by Richard Kithil, President
National Lightning Safety Institute
…treat lightning like a snake: if you see it or hear it take evasive
measures…
1.0 Summary.
Some unexpected situations present extreme danger - an
angry fer-de-lance, a Class VI rapid, crumbling cornices and rotten rock
- these can be perilous events. There is no defense for lightning's
"bolt-out-of-the-blue" occasional strike. But for the most part,
lightning safety is a risk management procedure. Early recognition of
the lightning hazard, with an awareness of defensive options, will
provide high levels of safety.
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COMMON MISCONCEPTIONS AND MYTHS.
1. Lightning never strikes twice… it strikes the Empire State Building
in NYC some 22-25 times per year !
2. Rubber tires or a foam pad will insulate me from lightning… it takes
about 10,000 volts to create a one inch spark. Lightning has millions of
volts and easily can jump 10-20 feet !
3. Lightning rods will protect my ropes course…lightning rods are
"preferential attachment points" for lightning. You do not want to
"draw" lightning to any area with people nearby.
4. We should get off the water when boating, canoeing or sailing…tall
trees and rocky outcrops along shore and on nearby land may be a more
dangerous place.
5. A cave is a safe place in a thunderstorm…if it is shallow cave, or an
old mine with metallics nearby, it can be a deadly location during
lightning.
------------------------------------------------------------------------
2.0 Atmospheric Physics 101.
At any one time around the planet, there
are 2000 thunderstorms and 100 lightning strikes to earth per second.
The frequency of lightning increases in the lower latitudes (closer to
the equator), and in the higher altitudes (mountainous terrain). In the
USA, central Florida experiences some 10-15 lightning strikes per sq.
km./yr. The Rocky Mountain west has about two thirds this activity.
Central Africa, parts of Southeast Asia, and the Latin American mountain
regions can experience two to three times as much lightning as central
Florida.
Lightning leaders from thunderclouds proceed in steps of tens of meters,
electrifying ground-based objects as they approach the earth.
Ground-based objects may launch lightning streamers to meet these
leaders. Streamers may be heard (some say they "sound like bacon
frying") and seen (we may notice our hair standing on end). A connecting
leader-streamer results in a closed circuit cloud-to-ground lightning
flash. Thunder accompanying it is the acoustic shock wave from the
electrical discharge. Thus, thunder and lightning are associated with
one another.
3.0 Flash/Bang.
We all possess a first-class lightning detection device,
built into our heads as standard equipment. By referencing the time in
seconds from seeing the lightning (the FLASH, or "F" ) to hearing the
accompanying thunder (the BANG, or "B"), we can range lightning's
distance. A "F" to "B" of five seconds equals lightning distance being
one mile away. A "F" to "B" of ten = two miles; a "F" to "B" of twenty =
four miles; a "F" to "B" of thirty = six miles; etc.
New information shows successive, sequential lightning strikes
(distances from Strike 1 to Strike 2 to Strike 3) can be some 6-8 miles
apart. Taking immediate defensive actions is recommended when lightning
is indicated within 6-8 miles. The next strike could be close enough to
be an immediate and severe threat.
Lightning is a capricious and random event. It cannot be predicted with
any accuracy. It cannot be prevented. Advanced planning in the form of a
risk management program is the best defense for maximum safety.
4.0 Standard lightning defenses.
The eco-tourism environment is
different from situations where substantial buildings or fully enclosed
metal vehicles are the recommended shelters. Lightning in remote terrain
creates dangerous conditions. Follow these guidelines:
LIGHTNING SAFETY TIPS.
AVOID: Avoid water. Avoid all metallic objects. Avoid the high ground.
Avoid solitary tall trees. Avoid close contact with others - spread out
15-20 ft. apart. Avoid contact with dissimilar objects (water & land;
boat & land; rock & ground; tree & ground). Avoid open spaces.
SEEK: Seek clumps of shrubs or trees of uniform height. Seek ditches,
trenches or the low ground. Seek a low, crouching position with feet
together with hands on ears to minimize acoujstic shock from thunder.
KEEP: Keep a high level of safety awareness for thirty minutes after the
last observed lightning or thunder.
5.0 Medical treatment and symptoms.
Treat the apparently dead first.
Immediately administer CPR to restore breathing. Eighty percent of
lightning strike victims survive the shock. Lightning strike victims do
not retain an electric charge and are safe to handle. Common lightning
aftereffects include impaired eyesight and loss of hearing. Electrical
burns should be treated as other burns.
Training in Lightning Safety can be provided by the National Lightning
Safety Institute
National Lightning Safety Institute
891 N. Hoover Ave.
Louisville, CO 80027
rich@lightningsafety.com
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