It is all too familiar. The skies suddenly darken, a distant rumble of thunder is heard and a vivid streak of lightning flashes across the sky, followed by a heavy downpour. So accustomed are we to this almost daily occurrence that we are in danger of disregarding the serious threat that lightning poses.
Severe lightning storms experienced throughout the months of March and April, have claimed the lives of several people across the country, even those who were within the purported sanctuary of their homes. The youngest of these victims were children within the ages of 9 to 12.
Rasini Rasanjali from Kiriella, Ratnapura, just nine years old was struck by a bolt of lightning while she lay asleep in her bed on April 11. A little more than a week later, a 12-year-old girl in the same area was struck by lightning. Down south in Hambantota, Tharushi Nimasha, a Grade two student was struck by lightning on March 14 while riding her bicycle in the rain.
The Department of Meteorology has recorded seven deaths due to lightning over the past two months. Their records reveal that there were four deaths in March and three deaths in April. The seven victims were from the areas of Tangalle, Akuressa, Pussellawa, Passara and two from Kiriella, the Deputy Director of the Meteorology Department S. R. Jayasekera told the Sunday Times.
There have also been several incidents that had left people badly injured. One of the more harrowing incidents occurred on March 27 when lightning struck a row of houses in Elpitiya injuring seven people.
“April is a typical month for lightning activity, with fluctuations in the weather on the same day,” says Meteorology Department Director, S.H. Kariyawasam. April may be over, but the lighting threat still continues he warns: “The conditions are favourable for lightning, so you can expect more thunderstorms in the coming days.”
Mr. Kariyawasam went on to say that death caused by lightning while people were indoors is not unheard of and that the most prevalent risk is of television antennas acting as a lighting conductor which transports the charge to television sets. Other lightning risks include electrocution while handling electrical equipment if the domestic circuit is affected by lightning. This can occur through induction.
In the case of little Rasini’s death which happened in what one would believe was ‘the safety of her home’, the Director sounded a warning note: “Very severe lightning can even travel through the steel rods in the walls. Lightning can even travel through glass if it is very severe.”
If a house is directly struck by lightning the electrical current can surge through wiring or plumbing, and travel through the building. It is advised that people refrain from taking showers during lightning, and stay clear of sinks and electrical equipment during a storm.
How does one protect one’s home from a power surge due to lightning? Electrical Consultants at Power Logic Engineers (Pvt) Ltd, say that depending on the type of building Surge Arresters can be installed which will divert the electricity from the surge into the earth.
Suggesting other methods of protecting households against power surges due to lightning, Mr. Kariyawasam says that using lightning conductors is an ideal way to reduce the chances of lightning travelling through a building.
Lightning conductors can be bought in stores, but they are costly. There are other simple cost-free measures that can be taken to protect your household. “Lightning travelling through antennas is quite possible, so people should disconnect their television sets, unplug electrical equipment and refrain from using laptops. They may also disconnect their domestic circuits,” he advised.
Discussions to repair Mihintale Maha Seya
Apart from the deaths caused by severe lighting, there has been a considerable amount of damage to households and buildings as well. The worst affected may well be the Mihintale Maha Seya, with almost 20 feet of a section of the third Pesawalalla damaged after being struck by lightning on April 23.
Explaining how the temple was affected, Chief Incumbent of the Mihintale Maha Seya, Sri Raathanajothi Ratanasara, said that the broken lightning conductor in the stupa was the cause. “When the lightning struck the broken conductor, instead of carrying the current to the earth, the current was spread through the Pesawallala.”
A discussion with Ministers in regard to repairing the heavily damaged Pesawallala will take place on May 3.
Former Director of the Meteorology Department K. R. Abhayasingha highlights the double threat of tornadoes and lightning
The first inter-monsoon season usually begins in mid-March, and ends in mid-May every year. Because of solar radiation falling nearly vertical into the Sri Lanka landmass during this period, the environmental conditions around us are very favourable for he development of huge convective clouds named Cumulonimbus, which are the generators of the twin hazards of tornadoes and lightning particularly during the afternoon and evening.
Every year we experience weather-related natural disasters caused directly or indirectly by rain, wind, high temperature, low temperature, mist, fog, and lightning. Taking precautionary steps to minimize deaths and property damage is vital. However, it is clear that most of us either forget or do not care about taking precautionary measures. Fatal incidents could be avoided if the precautions are taken in time.
Tornadoes are small scale, very energetic storms with strong gusty winds. These systems with very short life of 5-10 minutes are capable of causing physical damage to property directly by whirling winds and indirectly by flying objects and falling trees and other objects.
The sight of the dark, grey column and the roaring noise are warning alarms of an active tornado in the vicinity.
The size of a tornado averages about 100 metres across. Its destructive power is caused both by tremendous winds, which may exceed 100 metres per second, and by the great radial gradient of pressure, which causes explosive destruction of buildings etc. in its path.
During its short life time, a tornado moves in a horizontal direction at speeds about 2-3 metres per second. Sri Lankan tornadoes travel distances of 1-2 kilometres. In addition, the widths of our tornadoes have been found to be within 100-200 metres. As a result the effective area is limited to a comparatively small area like a single village or a part of a village.
Lightning is responsible for several deaths and damage. The electric current of a ground lightning flash is about 25000 Amperes (25000 A) and the potential difference between a charged thunder cloud and the earth is about 100 million Volts and the energy of a lightning flash is about 500 million watts.
Lightning causes hazards in environments both indoor and outdoor. Indoor lightning hazards can be caused by direct hits to buildings and by surge currents induced in supply service lines during thunderstorms. Both types can be prevented or at least minimzed by installation of protective technical instruments.
Lightning hazards are not always fatal. The extent of the damage depends on the path of the lighting discharge through the body and the intensity of the current. In case of lighting strikes to persons, first aid should be given to the victim before taking him for medical treatment.
The vulnerability of a thunderstorm depends on the location or the environment where people live or work. Avoid being in an open area in both tornadoes and lightning because the probability of a lightning flash striking directly and an flying object injuring a person is high when one is exposed to the environment.
Lightning: Safety measures
Do not have any conducting connection (like wires) between houses and the nearby trees.
In environments with
- Keep electrical instruments 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.
- As far as possible, avoid handling/touching electrical instruments like the 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 the 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. Especially avoid working in open air holding metal tools like a mammoty, knife or iron rods. If this cannot be avoided, crouch down, with feet together. Footwear or a layer of any non-absorbing material, such as a plastic sheet, offers some protection against ground currents.
- Do not seek shelter under or near isolated tall trees and on 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 low. 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 bicycles, or riding in any open vehicle such as a tractor.
- Avoid swimming or wading.
- Avoid touching or standing close to tall metal structures, wire fences and metal clothes lines.
- Limit the use of telephones when a thunderstorm is overhead.