Scorching hot days may have come to an end with the onset of the inter-monsoon period bringing with it wet days and a cooler clime, however, meteorologists warn of the accompanying dangers such as thunderstorms, lightning, flashfloods, rock falls and landslides.
Since October upto date 11 deaths have been reported due to lightning adding to the 37 deaths reported since January this year. The highest number of deaths was from Welikanda, Ratnapura, Kalutara, Horana, Polonnaruwa, Mahawilachchiya and Siyambalanduwa areas, with farmers and children being the majority of the victims.
Strong winds also damaged property in Moneragala, Hambantota, Polonnaruwa, Ampara, Embilipitiya, Puttalam and Dehiattakandiya areas.
Sri Lanka experiences two inter-monsoonal seasons, between the South-west monsoon and the North-east monsoon in March-April and October-November, respectively.
Meteorology Department Deputy Director M.D.Dayananda said lightning associated with thundershowers was a predominant feature of the inter-monsoon season.
He said the mornings will still be warm leading to the land getting heated and evaporation taking place. Towards evening strong spiral winds could even uproot trees and damage roofs.
He said dry zone areas like Moneragala and Puttalam are the areas that receive the heaviest inter-monsoon showers.
Heavy showers during a short period of time can also cause flash floods. During the end of last year floods in most parts of the country destroyed paddy cultivations and displaced families both in rural and urban areas.
Mr. Dayananda warned that all areas are vulnerable to lightning strikes. The majority of deaths were reported between 3 p.m. and 6 p.m.
Meteorology former director K.R. Abhayasinghe said Sri Lanka is affected by frequent cyclonic weather patterns during the second inter-monsoon season, resulting in widespread thundershowers. “The difference between a charged cloud and the earth is about 100 million volts and the energy of a lightning flash is about 500 million joules.
The life span of a thundercloud is short and fatal lightning strikes during that brief period. It is important to take necessary precautionary steps during that period as the lightning flash that follows can cause severe damage to life,” he said.
According to Mr. Abhayasinghe, if the time interval between a lightning flash and a thunder clap is less than 15 seconds, one should seek shelter in a protected are as there is imminent danger of the lightning striking nearby.
Lightning hazards can be minimised by taking precautionary measures that include;
- avoiding open areas like paddy fields, tea estates or play grounds
- avoiding working in open fields with metal tools such as a mammoty, knife and iron rods.
- If working in the open wear footwear or a layer of any non-conducting material, such as plastic sheet, to offer some protection against ground currents.
- When evening thunderstorms are forecast it is best to avoid being out in the open.
- Installing a good earth for the electric circuit of buildings, using power surge diverters, installing lightning conductors for buildings
- As powerful surges of a lightning travel through electric power supply cables, telephone cables and TV antenna cables, it is important to disconnect them from the main power supply. Television antennas should be disconnected from the television sets. As far as possible, avoid handling/touching electrical instruments like the refrigerator, electric iron, metal frame, TV and radio.
- One should also avoid touching or standing close to tall metal structures, wire fences and metal clothes lines. It is important to limit the use of telephones during a thunderstorm.
- One should not seek shelter under or near isolated tall trees and on high ground.
- Swimming, riding horses or bicycles or riding in any open vehicle such as a tractor should be avoided.
Lightning hazards are not always fatal. The state of the damage depends on the path of the lightning through the body and the intensity of the current. The body should be massaged in case of temporary paralysis due to a lightning strike.
Landslides Division of the National Building Research Organization (NBRO) chief R.M.S.Bandara also warned intense showers during a short period could result in rock falls and landslides. He said, last month there were several reports of incidents of rock fall incidents from Matale and Balangoda.
“The north-east monsoon will begin in December bringing rain to the eastern slopes of the central hills like Badulla, Matale, Nuwara-Eliya and Kandy districts. Landslide incidents are mainly reported during December and January,” he said adding that residents of these areas should be take necessary precautions during the next few months. |
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