There are almost 50 per cent more lightning strikes in the Westland District each year than anywhere else in the country.
Data from Metservice shows there are 9060 “cloud to ground” lightning strikes on average annually in the district.
The region with the next highest number is Canterbury where there are 5530 annual average strikes.
Just one place outside South Island is in the top five, Bay of Plenty, which has 3459 strikes a year. Auckland gets 900 and Wellington just 163.
Head of weather communications at MetService Lisa Murray told the Herald the Westland District is the perfect place for lightning to form.
“Most of our weather comes from the west. As that weather moves on to the country it gets pushed up over the land, and on the West Coast in particular it goes from sea level right up into the Southern Alps really quickly.
“When you lift air, it gets colder as you go up into the atmosphere and colder air holds less moisture so that excess moisture comes out as rain that can cause cloud. Then you can get these clouds turning into towering cumulus and then cumulus nimbus which are those thunderstorm clouds,” she said.
Murray said most of the strikes in Westland are along the ranges or Southern Alps.
National MP and former Westland Mayor Maureen Pugh knows all too well about the thunderstorms that can hit the district.
Earlier this year Pugh told the Herald she has been struck by lightning three times while on the West Coast.
On one occasion, she was running a bath and as she went to turn off the brass tap, lightning struck the house sending millions of volts through the copper pipe and hitting Pugh’s hand.
The MetService data shows you are least likely to be struck by lightning in Christchurch, which averages just 85 strikes a year.
And even though the Canterbury region has the second-highest number of strikes, 85 per cent fall in the high country – just 737 are recorded on the plains.
Murray said that’s because the lightning’s aleady happened as the weather front crossed the ranges.
“As that same air moves down the other side of the ranges, it’s much drier because it’s got rid of all the moisture and it warms up as it comes down.
“It would have to be a pretty massive thunderstorm coming in to reach all the way to Christchurch.”
But places like Christchurch can experience a different type of thunderstorm.
“We call them summer thunderstorms. The clouds bubble up due to the heat of the day. The air warms and rises and that gives the uplift, rather than the mountains.”
Murray said an example was seen in South Canterbury in 2019.
Hailstorms the size of golf balls were reported in Timaru, with the insurance bill reaching $170 million. More than 12,000 motor insurance claims were made as well as 5800 home and contents claims.
“The air likes to have warm air at the top and colder air at the bottom. If you have the reverse, the air doesn’t like that so it tries to correct it. That’s really key for a big thunderstorm.”
Murray said people being injured by lightning strikes is rare in New Zealand.
In the United States, 40-50 people are killed annually, but here there’s about one death every 5-10 years.
“Bear in mind America is a lot bigger, but there is also a lot of really open space, a lot of ranches that wouldn’t necessarily have the cover.”
The last known death from lightning in New Zealand was in 2008, when a 61-year-old and his horse were killed instantly after being struck.
Murray said pinpointing where thunderstorms will happen is one of the hardest things for forecasters to predict.
“All you can say is all the ingredients are there, you will probably see it but can’t say exactly where.
“It’s a bit like popcorn in a pot, you know that they’re going to pop but you don’t know which one will pop first.”
If you do find yourself caught in a storm, Murray has a few tips to keep you safe.
“I would not go out and play golf, for instance. If you’re holding a metal rod that is not a good idea.
“If you’re in a big open field, get as low to the ground as possible, curl up or lie flat.”
She said your car is a reasonably safe place.
“But if your car does get struck by lightning, don’t touch anything that is directly connected to the exterior of the car, such as the door handle – just wait until the fire brigade comes and can discharge the car for you.”
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