Lightning can be deadly, but forecasters can’t tell us where and when it will strike


Posted

October 18, 2018 08:37:09

It’s one of the world’s most dangerous weather phenomena, but you will never hear the word “lightning” mentioned in a forecast.

Electrical storms are one of nature’s most spectacular displays, but they can also have catastrophic consequences — triggering bushfires, destroying buildings, disrupting air traffic and in the worst-case scenario, causing death.

So why aren’t we warned about lightning in a weather forecast?

Meteorologists can’t pinpoint exactly where and when lightning will strike or how intense it will be.

But they can forecast the chance of a thunderstorm.

“As soon as we say thunderstorms, there will be lightning,” Bureau of Meteorology spokesman Neil Bennett said.

“Unfortunately there’s no real way of saying how many strikes or whether they’re even going to be cloud-to-ground … and we don’t have a way of detecting ahead of time where the lightning strike is going to occur.

“What we can do though, is we can forecast areas that are more likely to see a thunderstorm occurring, and the moment that we put a thunderstorm onto a forecast, there’s an assumption there will be lightning with that.”

A severe thunderstorm warning is issued if the system is likely to produce large hail, wind gusts above 90 km/h, heavy rainfall which may cause flash flooding or tornadoes, but lightning is not factored in.

It can, however, be detected and viewed on the bureau’s satellite.

Thunderstorms occur throughout Perth and regional areas all year round, but lightning is particularly prevalent during the warmer months.

Why lightning means take shelter

It is estimated that there are five to 10 deaths a year from lightning strikes in Australia and more than 100 people are seriously injured.

The devastation that lightning can cause was laid bare during the 2016 Waroona blaze — one of the worst bushfires in Western Australia’s history.

The fire, which killed two people, destroyed 181 homes and scorched 70,000 hectares of land, was sparked by lightning in state forest.

“The temperatures that (lightning strikes) generate are at an instantaneous moment hotter than the temperature of the sun, around 30,000 degrees Celsius,” Mr Bennett said.

“You can see vaporisation of sap in trees and that will cause trees to explode outwards.

“The electrical discharge can be fatal as well — it is a very dangerous weather phenomena.

“People do survive lightning strikes but it’s not something you should be actively seeking, you should be seeking shelter and finding a safe place to be.”

The hidden danger you may not know about

Grant Kirkby, a specialist in lightning risk mitigation, believes most people are blasé about the dangers associated with lightning.

“People generally think they’re bullet-proof and they’re indestructible and they don’t rate lightning as being a risk,” he said.

“If there’s a thunderstorm, they will go outside and watch it and they won’t for one minute think it could strike near them and affect them.”

But Mr Kirkby said the biggest risk associated with lightning cannot be seen.

A direct strike accounts for only 3 to 5 per cent of all injuries and death, while ground currents — which spread out over the ground after lightning strikes — account for up to 50 per cent.

“It’s an invisible risk — the risk isn’t necessarily what you see coming out of the sky, it’s the consequential effects associated with that,” he said.

“Where the lightning strikes the ground, the ground becomes highly electrified and if you’re within that area of ground electrification – what they call a hot zone – then you can be in some serious trouble if you’re too close.”

So where should you be when lightning strikes?

Mr Kirkby said the worst place to be during a lightning storm was outside, and worst still, under a tree.

“The best advice is if [a person] can hear or see lightning, they’re already at risk,” he said.

“Their best move would be to find some place indoors or within a metal roof vehicle.

“If they are out hopelessly exposed, never stand near a high object.”

Topics:

weather,

perth-6000,

wa



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