"WE HIKE THE WILDERNESS, SO THAT WE FILL THE SOUL, MILE AFTER ENDLESS MILE, WITH THE GOODNESS OF NATURE.”
Storms in the Drakensberg Wilderness
The
magnificence and tremendous impact of a storm in the Drakensberg has to
be seen to be believed. First come the black clouds, enmeshed with
billowing soft puff-balls of gleaming white. It grows ominously darker
and the clouds are heavy as lead. There is a distant growl of thunder.
And suddenly the storm is upon you. The cloud is split by a fiery
javelin of white-hot light, a sharp crack which merges instantly with
the mighty roll of thunder, and you know the dreaded thunderbolt has
struck not far from you. And then they come, one after another,
hammer-blows, and you stand appalled at the fury of the storm. Sometimes
so rapid are the discharges that the whole sky and the boiling clouds
seem to throb and glow with fire. Cataracts of flame pour down on the
earth, glowing like molten iron, and the roar of the storm is an
unending, deafening cacophony of sound.
No wonder
the ancients thought they were witnessing the anger and black hatred of
their gods. Modern science, of course, has explained much of the wonder
of the storm, especially the mechanics of lightning, but still there is
much that we do not know, much that is still unpredictable.
We know
that as the thundercloud builds up it becomes a huge dynamo, generating
millions of volts of electricity. Then a separation of electrical
charges takes place, the positive charge streaming to the top of the
cloud and the negative to the bottom.
Then, by
a complicated interaction of electrical forces, the negative charge at
the bottom of the cloud induces a positive charge on the earth below it.
As the cloud passes slowly over the countryside, it draws the positive
charge below on the ground after it, and the two drift together,
down-wind.
It is,
of course, a well-known fact that if a positive charge is brought into
contact with a negative charge, electrons flow from one to the other.
But the two charges do not necessarily have to touch. If they are
brought close enough together, the electrons will jump the gap, causing a
spark. The spark is nothing more than air intensely super-heated to 30
000 degrees Celsius in a split second. No wonder you hear a crack (the
air expanding with the heat) when you touch the two terminals of your
car battery together. And no wonder you hear a mighty roar of thunder,
and see a spear of light, when the lower terminal of the cloud and earth
come close enough together.
One consequence
of all this is that lightning, contrary to popular believe, does not
strike down. Actually, three things happen almost simultaneously. First
there is certainly a downward discharge of electricity, about one
million volts in barely one hundredth of a second. But then there is a
surge of high voltage electricity flashing back up the original path,
again in a minute fraction of a second. It is the second, upward flash
that does the killing. Lastly, there is a sustained and longer charge
between the cloud and the earth, lasting for about one-tenth of a
second. It is this charge that burns or melts the object struck. The
total voltage, in a single flash of lightning, can reach 100 million
volts. Of course, all this can also take place between one cloud and
another, if they are differently charged. High-speed photography has
proved all this.
Heat is
the main killer. When a tree is struck by lightning it looks as if the
bark has been split open. That is exactly what has happened. The intense
heat, passing through the core of the tree, causes the sap to expand
explosively, and to burst open the enclosing bark. The electric current
runs through the roots and trunk and out through the branches and
leaves, raising the temperature in the flash of a second to millions of
degrees centigrade.
Lightning is
completely unpredictable. There are certain general rules, but the main
rule appears to be that these are continually broken! For instance,
climbers are told to avoid high points during a storm, on the theory
that lightning will always strike the highest point. But often, sitting
on a hillside during a storm, you will see lightning striking down in
the valleys below. Even so, it is a wise precaution to choose low, flat
ground (not a slope) as a place to sit out a storm.
What other
precautions can one take? First of all, on no account shelter under an
isolated tree. Clumps of trees, or forests, are safer, but it is better
to even avoid these. Also, keep away from wire fences, posts, horses,
and cattle. If you are mounted, dismount and move away from your horse.
Drop anything metal you are carrying, and don’t, whatever you do, run
for shelter. Running seems to produce a magnetic field which can attract
lightning.
Deep caves are safe, but avoid shallow caves and overhangs, and also cracks and chimneys, especially if water is flowing down them.
The safest
place in a storm is a car or a building. There is some evidence that in
a dry storm the bodywork of a car can be damaged by lightning, but
there is no known case where a person sitting in a car has been killed
or even injured.
If you
have no car or house in which to shelter, the best course is to sit
down on some insulating material, such as a sleeping bag, draw your
knees up, put your arms around them, and sit the storm out. It is a good
idea to drape something like a cape around you. Don’t lie down and down
stand up. Above all, don’t panic. Remember that, statistically
speaking, it is extremely unlikely that you will be hit.
Actually, although African huts in the Drakensberg are often struck by lightning with fatal results (thatched
huts are potentially very dangerous, South Africa holds a world record
in this respect. Some years ago a hut in which 64 Africans were holding a
party was struck by lightning, and 61 were killed instantly.), very few climbers and hikers have been struck.
Two incidents
are worth mentioning. Years ago 2 climbers were standing in the middle
of a group of horses. Lightning struck and killed the 2 climbers and a
horse. Years later, at Injasuthi, a park Ranger, his girlfriend and a
dog was standing in one of the most exposed positions one could imagine –
the highest point on a bleak, remote and rock-scarred plateau, next to
some Protea trees - watching an approaching storm coming from Monks
Cowl. Then came a freak thunderbolt – one blinding flash of light – and
left all 3 dead.
Don’t take a chance, respect the mountains and her weather patterns, and always play it safe.
The End.
Safe Hiking.
References and Acknowledgements
From the book: Dragon’s Wrath – J Byrom/RO Pearce
Photos: ©Willem Pelser
Compiled by: Willem Pelser
No comments:
Post a Comment