The purpose of this document is to
provide a guide for personal safety during thunderstorms.
brief review of common medical problems encountered with a lightning
strike and appropriate first aid treatment is also included.
Anticipating a Thunderstorm
Keep 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
Safe Locations when there is choice
Do not remain
outdoors. Seek shelter in one of the following locations:
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
a substantial (normal headroom) metal-clad building
a large building, keeping away from windows and any appliances connected
to outside electrical conductors
City streets that are shielded
by nearby buildings
Avoid these if possible:
Flammable hydrocarbons and
Standing near a Lightning protection down-conductor,
mast, or earthing system.
Communications towers, and tall metallic
Any use of fixed line telephones, especially corded headsets.
(Cordless & mobile excluded)
Metal hair clips, metal clips
on helmets, keys in pockets etc.
buildings, barns, sheds
Areas on tops of buildings
fields, sports arenas, golf courses, car parks
Areas near wire fences, clothes lines, overhead
wires, pipelines and railroad tracks
Standing beneath isolated
trees, or touching or standing near any tree
tractors or other open roof farm machinery, golf carts, bicycles,
horse riding or motorcycles, non-metal top or open automobiles
Contact with metal objects and electrical appliances
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High Risk Workgroups
Statistics tell 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.
will include, (but are not limited to):
Linesman and Electrical
workers who work with switchboards, and copper conductors
and cabling installers
Railway line installation and maintenance
and Orchard workers
Pipe-line 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
In recent years, Australian Lightning
Strike Statistics have included:
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
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)
in a group, stand at least 3 metres apart
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
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.
Contact potential - physical contact with
struck object has similar consequences to direct strike.
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 usually temporary.
- 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.
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 is dead.
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 injury.
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.
After 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
The 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
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.
Some 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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and Warning Technologies
Lightning warning and detection
systems fall into two categories:
Those systems that warn of
the conditions that precede a lightning discharge "A Lightning Warning
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 warning.
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.
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 mills.
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 events.
Lightning Warning Systems comprise the following types:
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
the local 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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Safety for Outdoor Workers
Lightning 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 location.
The following steps are
1. Regularly monitor weather conditions and local
weather forecasts prior to scheduled activities.
and resumption of work activities should be planned in advance,
in conjunction with a Lightning Risk Policy
of SAFE shelters is essential. SAFE evacuation sites include:
Fully 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
8. Lightning's remote distance is easy to
calculate: If you hear thunder, the associated lightning is within
9. Suspend activities, allowing sufficient
time to get to shelter. Of course, different distances to safety
will determine different times to suspend activities.
Be aware of your surroundings and the nearest safe area.
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