ST Explains: Will climate change increase the likelihood of lightning strikes in Singapore?
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Singapore has one of the highest lightning rates in the world, with strikes occasionally harming people and infrastructure.
PHOTO: PAUL LEE
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SINGAPORE - Located near the Equator, Singapore has become a contender for the title of the world’s lightning capital with its many thunderstorms.
The country has one of the highest lightning strike rates in the world, with strikes occasionally harming people and infrastructure. On June 3, one such bolt sparked a fire
In December 2023, three workers on the roof of a Build-To-Order HDB block in Bartley were taken to hospital after a bolt of lightning struck near them
Using the latest data from the National Environment Agency’s Meteorological Service Singapore (MSS), The Straits Times looks at why Singapore is a lightning magnet
Why is Singapore affected by so much lightning?
Lightning is a large electrical spark caused by the difference in charges between storm clouds and the ground, or within the clouds. It discharges in a blinding flash.
Annually, on average, there are 175 days when lightning is detected in Singapore, based on records at the Changi climate station, the MSS told ST. This amounts to nearly one in every two days each year.
Thunderstorms that occur all year round in Singapore arise from two major rain-bearing weather systems.
In the first system, localised thunderstorms are brought about by breeze carrying moisture from the sea inland. The moist air mixes with rising warm land air caused by the sun and, under unstable conditions, forms a thunderstorm.
The second system, Sumatra squalls, is a line of thunderstorms that travels towards Singapore after developing over the island of Sumatra or the Strait of Malacca.
About 20 per cent of lightning strikes hit the ground, making these the most dangerous kind of bolts.
According to MSS’ lightning information service, 11 of such cloud-to-ground lightning strikes were detected between 5.20pm and 5.24pm near Kranji MRT station on June 3, shortly before a bolt was reported to have damaged trackside equipment
Even in the absence of a thunderstorm at a location, lightning from a thunderstorm cloud more than 10km away, also known as a bolt from the blue, can still strike the ground in the location.
A lightning strike damaged components in a power control box near Kranji MRT station, causing a power trip on June 3.
PHOTO: SMRT FACEBOOK
When does Singapore get the most lightning?
The highest lightning activity occurs in April, May, October and November, said MSS.
These are known as the inter-monsoon months, when the predominantly light and variable winds spur the development of intense localised thunderstorms.
On average, the inter-monsoon months account for about half of the lightning occurrences detected here in a year, said MSS.
Will climate change increase the frequency of lightning?
Associate Professor Steve Yim from Nanyang Technological University’s Asian School of the Environment said: “Generally speaking, climate change could increase the frequency of lightning due to the enhanced convection and more moisture in the atmosphere.”
Theoretically, soaring temperatures worldwide due to climate change could boost the odds of a thunderstorm.
A warmer atmosphere holds more moisture, or about 7 per cent more moisture per 1 deg C of warming, according to the Royal Meteorological Society in the UK.
In 2014, scientists from the University of California, Berkeley, and State University of New York predicted that the number of lightning strikes in the US would rise by about 12 per cent for every 1 deg C rise in global average air temperature.
In the tropics, more energy will need to be released when the atmosphere closest to the earth’s surface is heated, said Prof Yim.
This could result in more lightning, as convection currents – heat-driven cycles caused by differences in temperature – will become more frequent, he added.
However, large uncertainties still exist in models to represent the interaction of aerosols and clouds, which affect the accuracy in forecasting lightning activity, said Prof Yim.
Meanwhile, there has been no significant change in the annual number of days that lightning was recorded in Changi over the past 30 years, according to MSS.
The rate of lightning strikes has also not changed significantly.
How dangerous is lightning?
Those struck by lightning can get injuries such as burns, cataracts and fractured skulls. They can also get psychological injuries such as post-traumatic stress disorder or depression.
Only about 10 per cent of people who are struck by lightning are killed, according to statistics from the US National Weather Service.
In February, a footballer in Indonesia died after he was struck by lightning
In 2011, a man died after he and another man were struck by lightning while fishing at Coney Island.
Lightning strikes can damage equipment, but infrastructure such as lighting rods has been put in place to shield people in Singapore.
For instance, people in trains are safe during a lightning storm as the trains are protected by an enclosure made of conductive material, also known as a Faraday cage.
What can I do to prevent myself from getting struck by lightning?
Lightning that hits the ground tends to strike conductive objects at a higher level first.
Said Prof Yim: “But people should still avoid being exposed to lightning in an open space. Lightning in Singapore is typically strong, so the safest way is to stay under a shelter.”
While technology has allowed countries to forecast lightning events more accurately, it is still impossible to forecast all such events, especially during seasons when convection is strong, he added.
The public can also take these precautions, as advised by MSS, in the event of lightning strikes:
Do not stay in or near water bodies such as the sea or swimming pool.
Minimise the use of electrical appliances.
Avoid holding metal objects like golf clubs.
Do not seek shelter under tall trees or small structures like a tent. Instead, seek shelter in a building or a car.
Wait at least 30 minutes after thunder is last heard before resuming outdoor activities.
The latest weather information can be accessed at this website.
