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The purpose of this document is
to provide a guide for personal safety during thunderstorms.
A brief review of common medical problems encountered with
a lightning strike and appropriate first aid treatment is also
Anticipating a Thunderstorm
a constant lookout for thunderstorm clouds in the region. They
can develop in as little as 15 minutes. If thunder is heard
and intra-cloud /cloud to ground lightning can be seen, you
are already in a higher risk situation.
Once thunder can
be heard, keep estimating the distance to the lightning activity
by using the Flash to Bang reckoning method. This is a mental
calculation that anyone can do simply by counting the delay
between seeing a lightning flash, to hearing the audible thunder
associated with the flash.
The rule of thumb is that every
3 seconds of delay between a flash to thunder, equates to a
distance of 1 kilometer, so where 30 second flash-to-thunder
time interval, the lightning activity is about 10 km away.
Data from lightning location systems shows that you
should seek a safe location whenever the flash-to-thunder time
( Flash to Bang) interval is less than 30 seconds or 10 km distance
to the lightning activity.
Safe Locations when there is choice
Do not remain outdoors. Seek shelter in one of the following
Within a dedicated Safe area such as any
area that is protected by a Lightning Protection System
Inside a metal-skinned car, other vehicle, or metal boat/ship
with a metal roof
Inside a substantial (normal headroom)
Inside a large building, keeping away
from windows and any appliances connected to outside electrical
City streets that are shielded by nearby building
Avoid these if possible:
Standing near a Lightning protection down-conductor,
mast, or earthing system.
Communications towers, and tall
Any use of fixed line telephones, especially
corded headsets. (Cordless & mobile excluded)
clips, metal clips on helmets, keys in pockets etc.
Small, unprotected buildings, barns, sheds
Areas on tops
Open fields, sports arenas, golf courses,
Swimming pools, lakes, seashores
wire fences, clothes-lines, overhead wires, pipe-lines and railroad
Standing beneath isolated trees, or touching or
standing near any tree
Riding/driving tractors or other
open roof farm machinery, golf carts, bicycles, horse riding
or motorcycles, non-metal top or open automobiles
with metal objects and electrical appliances
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High Risk Workgroups
us that there are some specific activities which regularly contribute
to ongoing lightning statistics, and there are some specific
workgroups, which it is obvious that these need to be considered
more closely and should be considered higher risk activities.
These groups will include, (but are not limited to):
Linesman and Electrical workers who works with switchboards,
and copper conductors
Telephone and cabling installers
Railway line installation and maintenance workers
Vineyard and Orchard workers
installers and maintenance workers
Emergency Services Workers
There are also many sporting and recreational activities
which have been major contributors to lightning fatality and
ongoing injury statistics:
In recent years, Australian
Lightning Strike Statistics have included:
Dump Truck Driver
Road Train Driver
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What to do if
the safest action is not possible
If the thunderstorm
is above you (flash-to-thunder time < 5 seconds) and you are
not able to take the action suggested above , then all you can
do is minimise the risk of being struck, or affected by the
indirect effects of lightning.
You should then try to:
Seek a depressed area; avoid high places
Keep away from
large isolated trees; (however, some protection is afforded
in a forest if care is taken not to touch or stand too close
to any particular tree)
If in a group, stand at least 3
If hopelessly isolated in an exposed area
and your hair stands on end, this is indicative that the e-
fields at ground level , are rising very fast, and that lightning
is about to strike, therefore assume a crouched position with
your feet together, or sit with your feet tucked in close to
How lightning injures and kills
Direct strike - statistics show that death resulted in over
70 % of cases.
Side flash - e.g. standing near a tree -
this can be as serious as a direct strike.
- physical contact with struck object has similar consequences
to direct strike.
Step voltage - lightning impulse traveling
through/on ground and may pass through one limb/part and out
another. Injuries include burns and paralysis but these are
Surge propagation - person close to or
in contact with an electrical appliance or power /communication
line. Serious injury is not common but a number of deaths have
resulted from telephone usage.
First Aid treatment
Contrary to popular belief and urban mythology, there is no
danger in touching a person who has been struck by lightning.
First aid is required urgently and should be started without
delay. Breathing can be restored using EAR and blood circulation
by CPR. These procedures must be continued until breathing/circulation
is restored, or it can be medically confirmed that the patient
Lightning victims are sometimes thrown violently
against an object, or are hit by flying fragments (e.g., a shattered
tree), so first aid may have to include treatment for traumatic
The 30/30 Rule
The 3030 Rule states that when
you see lightning, count the time until you hear the associated
thunder, and if this time delay is 30 seconds or less, go immediately
to a safe location as described above.
If you cannot
see the lightning, just hearing the thunder means you are most
likely to already be within striking range, and it is time to
seek whatever appropriate shelter is available.
the storm conditions have apparently dissipated or moved on,
wait a further 30 minutes, after hearing the last thunder before
leaving the safe area location. Should thunder be heard within
this period, recount from the last thunder heard.
3030 Rule is best suited for existing thunderstorms moving
into the area. However, it cannot predict or protect against
a first lightning strike. Thunderstorms can develop overhead
where there will be no prior notice that a storm is incoming.
Be alert to changes in sky conditions portending thunderstorm
development directly overhead.
Larger outdoor activities,
with longer evacuation times, may require a longer lead-time
than implied by the 3030 Rule.
When lightning threatens,
go immediately to a safer location. Do not hesitate. The lightning
casualty statistics are full of stories where persons who were
just about to make it to safety, when they were struck. Even
a few extra minutes lead time can be life saving.
might discount the odds of the lightning risk as being greater
than winning a lottery.
Just remember there are plenty
of lottery winners every week!
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Detection and Warning Technologies
warning and detection systems fall into two categories:
Those systems that warn of the conditions that preceed a lightning
discharge "A Lightning Warning System"
Those that report
on historic events, albeit only seconds old. "A Lightning Detector"
Lightning Detectors include the following types:
Radio Frequency RF Detectors
These are typically
handheld devices which measure the unique Radio Frequency bursts
produced by active lightning, and measure the amplitudes of
the associated waveforms, thereby can very accurately determine
the approximate distances to remote active lightning, and in
some instances can determine the direction of the threat, can
alert to any detected approach towards the users location, the
approach speed, as well as he estimated time of arrival and
estimated to clear.
These devices are very cost effective,
but they do have limitations, that is they can only detect active
lightning and they cannot provide any level of pre lightning
Although highly dependent
upon other conditions such as rainfall, fog and other visibility
issues, these devices can provide warning as they detect the
light changes from cloud-to- cloud and cloud to ground lightning.
Typically they have a limited range of only about 15 to 20 Nautical
miles from the users location.
Optical detectors are
also used quite successfully by NASA on satellite platforms
for monitoring thunderstorms without the terrestrial visibility
issues. These are not recommended for use in lightning safety
and are more suited to meteorological use in statistical recording.
These are multi-station devices,
which are far more costly than the RF type detectors. These
devices measure lightning strike data more precisely, and then
usually require a skilled operator. These systems record information
after lightning has occurred where the data is manipulated and
then trended. Organisations like NASA would operate this type
of equipment in conjunction with more expensive local field
GPATS are an Australian company
who operate a National Lightning Detection Network, which networks
with many storm sensing antennae located across Australia. These
Sensors provide live data back to a main computer, which processes
the strike data in conjunction with information from other sensors
where Lightning strike data is able to be triangulated, with
a strike location accuracy of some 500 mtrs able to be given.
This data is archived and can be retrieved at a later date.
This data is available live and is available by subscription.
Lightning strike data can also be retrieved for a fee
where organizations are looking for forensic analysis of lightning
Lightning Warning Systems comprise the
Atmospheric Field Mill Monitors
These devices measure the potential gradient (voltage) changes
of the earth's negative electric field and report any changes
as ambient thresholds build to avalanche and breakdown.
These are quite expensive compared to the aforementioned
lightning detectors, and are typically used in Aerospace, Munitions
manufacture, Rocket Triggered Lightning Research activities
as well as Golfing, Spaceport, munitions and defence applications.
This is a predictive type of system that provides forewarning
that conditions are becoming unstable and highly charged.
The Corona Point Discharge Sensor
operates when it is exposed within an electrostatic field, and
as an electrostatic field increases, the rate of discharge increases
exponentially as a function of field strength. Current flow
is the result which can be used by proprietary electronics of
the LWS, to sense the presence of conditions which preceed and
occur during lightning activity.
The LWS sensor requires
a sharp needle to create point discharge, which is also dependent
on the electrostatic potential.
Corona point has been
used in conjunction with vibrating reed as well as RF detection
to create a hybrid system which uses multiple monitoring methods.
It is a proven and effective tool that monitors
ambient conditions, and measures the static electro magnetic
fields over an area. This level of measurable information enables
a decision to be made prior to the onset of an electrical storm
developing over a local area, as opposed to alerting after lightning
has already occurred.
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Lightning Safety for Outdoor Workers
safety awareness should be a priority at every outdoor facility
and operation, where education is the single most important
means to achieving this goal.
The number one rule is
that workers need to always consider their own situational safety,
and those who may find themselves exposed to the risk should
always recognize and anticipate their exposure to a changing
or high-risk situation, and where appropriate move to a lower-risk
The following steps are suggested:
1. Regularly monitor weather conditions and local weather forecasts
prior to scheduled activities.
2. Suspension and resumption
of work activities should be planned in advance, in conjunction
with a Lightning Risk Policy
3. Understanding of SAFE
shelters is essential. SAFE evacuation sites include:
enclosed metal vehicles with windows up
4. UNSAFE SHELTER AREAS include all
outdoor metal objects, like power poles, fences and gates, high
mast light poles, electrical equipment, mowing and road machinery.
AVOID solitary trees.
AVOID open fields.
AVOID high ground and caves.
5. If you feel your hair
standing on end, and/or hear "crackling noises," you are in
lightning's electric field. If caught outside during close lightning
activity, immediately remove metal objects (including baseball
cap, jewellery, belts, car keys etc), place your feet together,
duck your head, and crouch down low with hands on knees.
6. Wait a minimum of 30 minutes from the last observed lightning
or thunder before resuming activities. Be extra cautious during
this phase as the storm may not be over.
7. People who
have been struck by lightning do not carry an electrical charge
and are safe to handle. Apply first aid immediately if you are
qualified to do so. Get emergency help promptly.
remote distance is easy to calculate: If you hear thunder, the
associated lightning is within audible range
activities, allowing sufficient time to get to shelter. Of course,
different distances to safety will determine different times
to suspend activities.
10. Be aware of your surroundings
and the nearest safe area.
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