Kerala has been facing severe losses due to heavy rainfall and several deaths due to lightning. Kerala is, in fact, one of the regions that sees one of the heaviest thunderstorm activities in India and a heavy death toll almost every year during the April-May pr-monsoon season and the October-November North-East monsoon season. About 70 people die on the average each year and more than one hundred people suffer injuries due to lightning. Many of these can be prevented by following some simple precautionary measures.
I give here a brochure originally prepared by Dr. S. Murali Das and published by Centre for Earth Science Studies, Thiruvananthapuram, Kerala, India (Get the English version here: English_Brochure_PDF_160803 and the Malayalam one here:Malayalam_Brochure_PDF_160803)
Remember that lightning is an electrical discharge that comes with great power: millions of volts and tens of thousands of ampere current. Hence small things like the short air gap in switches or the insulation of the rubber/leather on shoes are not capable of stopping the electricity. Hence one has to try to remain in safe places during a thunderstorm and ensure that all electrical equipment are disconnected from electrical connections before thunderstorms come near your place.In Kerala, which has thick vegetation almost everywhere, lighting that strikes a tree near your house can send strong electric currents through the ground, which can cause high potential difference between two points on the ground. This can sometimes be strong enough to kill a person. Hence it is not advisable to lie down on the ground or even keep your feet apart. This current can come inside houses and has been the cause of several deaths.
The safest places to be during a thunderstorm are vehicles with fully covered vehicles with metallic bodies (like cars and buses with metal on top and sides) and concrete buildings with lightning conductors properly installed. Riding two-wheelers is very unsafe. Traditional buildings with tiled roof or thatched roof do not offer any protection from lightning unless a lightning protection system is properly designed and installed.
Never stand in an open place or go for swimming or fishing in a large pond, lake or the sea. Never stand near a tall tree. There have been several deaths when people went to untie a cow tied to a tree or to pick clothes spread outside for drying. Tall trees can attract lightning to themselves and anyone standing nearby can be affected. It can be conducted through a rope tied to it, especially if it is wet.
Wires/cables coming into a house from outside, such as the power line, telephone line or the television cable can bring lightning current into the house and cause damage or death. Hence keep away from all of them. However, there would be no problem in using a mobile phone or a cordless one. Do not stand near windows or doors, especially if you are wearing ornaments or holding metallic objects.The safest thing would be to sit on a wooden chair in the middle of the room with your feet close together or lie down on a wooden cot.
There are several things that should not be done during a thunderstorm. Some of the common mistakes are:
- Going to untie cattle or to collect clothes from a clothesline tied to a tree (often coconut tree)
- Lie down on the ground or stand with feet apart outdoors or indoors on the ground floor
- Go fishing in a pond/lake/sea or play football/cricket in a large ground
- Stand close to a tall tree or any other tall unprotected object
- Speak over a land phone connection
- Ride two-wheelers
- Try to disconnect television or other equipment from power connection
- Stand near window wearing gold ornaments or holding metallic vessels
- Take shower bath or collect water from a pipe
- Walk in open space holding umbrella with metal frame
- Speak over mobile phone or cordless phone
- Travel in a car or bus with fully metallic body without touching its metal parts
- Cook in a traditional kitchen with firewood (won’t be safe in a house with tiled or thatched roof without lighting conductor installed)