Scouts-L Mail Archive for August of 1999: Lightning while camping Part II
Lightning while camping Part II
Tue, 10 Aug 1999 00:38:58 -0500
(continued from previous posting)
5. Large clusters of dense trees are much safer than
one or more "lone trees" in an open area. But never
stand close to or shelter directly under any tree, because if it
is struck, the energy can also travel down the sap under the
bark and often vaporizes the sap, causing the tree to
explode much like a grenade. Additionally since folks are
"nice warm bags of conductive salt water" they tend to serve
(inadvertantly) well as efficient paths to ground; yet
another major reason to stay away from trees or other
natural "lightning rods." Avoid power poles/lines, fences, and
similar structures as well. Fences can conduct discharges
over long distances and cause serious injury.
In outdoor settings, the most risky areas tend to be high
rocky outcrops, followed by open meadows and lone trees,
and of course on any open water. Cabless vehicles
and machinery are also very vulnerable. Outdoor areas that are
typically somewhat safer include: where a valley floor
adjoins the base of a mountain; and in dense forested areas
either on valley floors or lowest sides of mountains.
6. When a lightning bolt strikes a tree or other
object, it follows the path of least resistance
and is dissipated in the ground; but in this
process, the ground is also energized temporarily, so if
a person is standing close to the discharge point, even though
they may not be struck directly by the bolt, the "ground
wave effect" can cause electrical energy to travel up one leg
and through their heart, and back down the other leg, thus
causing the heart to go into ventricular fibrillation and
cease beating normally. Ground wave phenomenon is often
responsible for affecting many people on golf courses or open meadows
even though they were not directly hit by the bolt.
This also explains why herds of cattle and sheep in close
proximity are also often killed in large numbers.
In many cases where no serious
internal or neurological damage has occurred,
Ventricular fibrillation is reversible if CPR is promptly applied
and paramedics are summoned to convert the heart back into
normal sinus rhythm with a defibrillator and medications.
However this must be done quickly as CPR can
only sustain life for a short time without normal heartbeat.
Some camps, golf courses and athletic venues are getting Automatic
External Defibrillators (AED) for their medical staff just
to have on hand for sudden cardiac arrests. As noted in
other posts, there can be long-term neurological and physiological
effects suffered by victims of seemingly minor lightning strikes who
otherwise recover from the experience and may be released from
the hospital after a short stay for "observation." Any victim
of a lightning strike, no matter how minor, should always be
medically evaluated due to potential post-traumatic complications.
7. The "Lightning Safe Position" (LSP) described by Jack
has been slightly modified to include placing hands over
ears to avoid sound damage to ears if a bolt strikes
close by. The LSP will often prevent the "ground
wave" from causing fibrillation of the heart, and lessen the
possibility of a direct strike as well due to the lowered body profile.
The feet should be as close together as possible, and it's even
better to be crouched on a non-conductive material like a foam pad,
nylon rope or non-metallic pack; And, as Cooper Wright suggests, a group
should spread out very widely to also lessen the probability of
multiple casualties in a potential strike zone. Thus if a strike
occurs, chances are there will be fewer victims;
those unaffected can render CPR and go for help if necessary.
8. Camping presents a special challenge since campers often
are not afforded the opportunity to shelter either in a
building or in a car. So it is important to look for
other sources of shelter, in anticipation of a possible
electrical storm, which can be quickly accessed well
before the storm arrives. Prevention and anticipation
of the danger can save lives.
9. Avoid sheltering under shallow rock outcroppings or
caves, as lightning can travel down these paths through
crevices and strike those sheltering under them. Deep caves
are somewhat safer, but if there are crevices to the surface
there is still some danger.
10. Rock Climbers and mountain climbers
are in especially great peril if caught on a rock face in
an electrical storm. Wet nylon climbing ropes can serve as
conductors and transmit energy from one climber to another; metal
climbing hardware carried on harnesses is also a hazard.
Again, planning to have emergency and rapid evacuation to
a safer area is the best alternative, well in advance of the
arrival of a storm. Postponing activities
in such threatening conditions may prevent tragedies.
11. While sheltering in tents that have wood pallet floors
is preferable to those with no floors, or to being out in
the open, tents are not the safest place to be in a severe storm;
There are cases in which campers have been struck while in tents
mounted on wood pallets, so there are no guarantees;
thus, temporarily sheltering in a safer alternative such as
a building or vehicle would be preferable if at all possible.
Contingency plans to evacuate campers to buildings or multiple
vehicles would be a good backup measure when severe storms threaten.
12. Don't forget that severe storms also pose other hazards
such as tornadoes, large hail and flash flooding of normally dry streambeds
and gullies. This effect was tragically noted in Switzerland when
a number of youth were killed in a flash flood of a river which
originated from a severe storm very far away from them. Flash
flooding is also a serious problem in the mountains and in
desert country such as the southwest. Thus, planning for activities
and campsites should also avoid high risk areas.
Bob Amick, EMT-B, Advisor, Venturing Crew/SSS 72, Boulder, CO
Longs Peak Council Venturing/Exploring Training, Camping Committees
American Red Cross Community Disaster Education Instructor