Revise the acts of lightning

Before its second peak:

K. R. Abhayasingha, Former Director of Meteorology

Regular readers and listeners of the media know very well that the most vulnerable climatic season, the First Inter Monsoon season from mid-March to mid-May, of our country when lightning hazards are plenty is already gone. You are now aware that the killer lightning has caused death to more than 20 lives during last first Inter Monsoon Season, according to the information from Department of Meteorology (DOM) and Disaster Management Center (DMC).

The warning of lightning threat was heard a number of times even after the First Inter Monsoon season because the bad wether with thunder storms accompanied by lightning flashes occur in any atmospheric condition with greater probability of developing a particular type of clouds named Cumulonimbus. The environmental conditions during the First Inter Monsoon season are very favourable for development of the Cumulonimbus clouds over the Sri Lanka landmass.

The second peak of thunder storms is the forthcoming Second Inter Monsoon season which persists over Sri Lanka during October-November which coincides with sun shining over head many parts of the country.

If analyzed in the lightning hazards recorded in our country during last First Inter Monsoon season you will realize that it is due to the carelessness of the victims in taking necessary precautions against lightning has resulted in most of the tragedies. The weakness of many of us is the optimism leading to the thinking that nothing will happen to self. This optimistic thinking has resulted in failures in taking the precautionary measures to save the life and property from lightening.

Lightning is very much powerful as it carries an electric current of several thousands of Amperes under a potential of about 100 million volts. You can compare yourself the strength of a lightning flash with that of the current of our domestic power lines which is about 15 Amperes under 230 volts.

No one, irrespective of the gender, age, race or nationality, can play fool with lightning flashes. It causes natural disasters like killing and injuring people and animals and also damaging property.

It is worth revising the protective measures against lightning before the next Inter monsoon season, second peak of thunder storms. This is the prime time for everybody to revise our knowledge of lightning, its hazards and mitigation of lightning hazards as well.

Domestic (indoor) lightning hazards, particularly property damages, are likely to increase along with the increasing trend of usage of modern technology in buildings. But these hazards can be easily controlled through the installation of protective devices in buildings. If the people are keen to introduce the available protective methods, the managing the domestic lightning hazards is not a significant problem.

The lightning surges, instant high current, that flow to inside the buildings through conductive connections with the outside metallic structures, will ultimately flow to the earth in a very short time through any available, mostly conductive, material inside the buildings. Domestic power circuits, reinforced iron bars inside concrete slabs and columns, electrical appliances, steel furniture, steel window or door frames and rods, nails and other metal parts fixed on walls. mercury paintings of mirrors etc. are some of materials supporting to approaching lightning current in thunderstorms. In such cases, the large electric currents associated with lightning may cause complete destruction, bursts, burns, scattering of objects and even death of inhabitants through side flashes.

Buildings can be affected by lightning directly or indirectly and buildings should be protected first with a good, standard lightning arrestor (lightning rod) as a protection system against direct effects.

In addition to the lightning arresters all buildings with any mode of connection with the outside through conductive materials must be protected with electronic instruments called Surge Divertors to stop the lightning surges intruding the building.

The main helper in reducing the hazards caused by intruding lightning surges through conductive connection with outside is the earth rod of any building.

Therefore, care should be taken to install a good earth rod at any building with main power supply and also to maintain it properly. There are a few very common reasons for the earth rods and earth circuits to have deteriorated characteristics. Some of them are -

* Decay of earth rods (with time),

* Poor connection of earth wire to earth rod,

* Corrosion,

* Disconnection of the earth wire and

* Dryness of soil around earth rod.

Following are some of the precautionary steps to prevent or at least to minimize the hazards caused by lightning strikes and surges.

In environments with thunderstorms,

* electrical instruments should be disconnected from the main power supply.

* Television antennas should be disconnected from the television sets and connected to a properly installed earth rod. If this is not possible, the antenna socket should be placed close to the earth outside the house.

* Avoid handling/touching electrical instruments like refrigerator, electric iron, metal frame, TV, and radio.

* Find shelter in a safe place to avoid exposing yourself to the open air. If the time interval between lightning flash and hearing thunder becomes less than 15 seconds, move quickly to a protected location as there is immediate danger of a lightning strike nearby.

* Try to avoid loitering in open areas like paddy fields, tea estates or playgrounds. Specially avoid working in open air holding metal tools like mammoty, knife and iron rods. If this cannot be avoided, crouch down, single, with feet together. Footwear or a layer of any non-absorbing material, such as plastic sheet, offers some protection against ground currents.

* Do not seek shelter under or near isolated tall trees and in high grounds. If the vicinity of a tree cannot be avoided, seek a position just beyond the spread of the foliage.

* By sitting down or lying down reduce the effective height of the body

* If in an open boat keep a low profile. Additional protection is gained by anchoring, under relatively high objects such as jetties and bridges, provided that no direct contact is made with them.

* Avoid riding horses or bicycles, or riding in any open vehicle such as a tractor.

* Avoid swimming or wading in the rivers, ponds or water holes.

* Avoid touching or standing close to tall metal structures, wire fences and metal clothes lines.

* Limit the use of cable telephones when a thunderstorm is overhead. Use a mobile phone to communicate in urgent cases.

Lightning hazards are not fatal always. The state of the damage depends on the path of the lightning discharge through the body and the intensity of the current. In case of lightning strikes to persons, first aid should be given to the diseased before taking him for medical treatments.

Body should be massaged to treat in case of temporary paralysis due to lightning strikes. If respiration is disturbed, artificial respiration should be tried. This could be done by blowing air into the patent’s body through his mouth.

In many cases, massage and artificial respiration have to be given simultaneously. There is no danger in touching, holding or carrying a person struck by lightning.

The vulnerability of a thunderstorm depends on the location or the environment where people live or work. Being in an open area should be avoided in thunderstorms because the probability of lightning flashes striking directly is high when one is exposed to the environment.