Nelson was strafed by lightning in a powerful storm that knocked out power, damaged houses and ripped up trees including many in historic Isel Park.
Nelson weather forecaster John Mathieson said the storm, which struck just before 10pm on Thursday and was centred over the Moutere and Mahana, was associated with the deep low pressure system moving over the mid South Island. It was not connected to the weather system that earlier struck Auckland from the north Tasman, which spawned lethal tornados.
Stoke appeared to have borne the brunt of the storm's localised fury, possibly the result of a downburst from the thundercloud, Mr Mathieson said.
Stoke Volunteer Fire Brigade senior station officer Tane Simpson said there was a substantial amount of damage through a small part of Stoke, in a short space of time. He said a roof was lifted off a house in Leicester St and the owner was picking up pieces of it 200-300 metres up the street as the fire service was trying to fix his roof. His caravan was also damaged.
The fire service also had to clear a tree from a driveway in Exeter St so a person on dialysis could get out. He believed the house was without power.
"There was a lot of debris lying on the road in about a two block radius. It was like something touched down had a go and then disappeared."
Isel Park is now closed until further notice because of damaged trees and continuing danger from falling branches.
The city council said yesterday that almost as many trees were damaged in the historic park as in the 2008 windstorm, which destroyed a third of its heritage trees.
Alistair Papps who lives in the historic Isel House, said the house shook. "It was a really strange wind, something I have not experienced before. It seemed like there was a lot of pressure. It was unnerving."
His wife, curator Sally Papps, said six significant heritage trees and more than 30 other trees were damaged.
A tulip tree, believed to be the biggest in the southern hemisphere split and fell by a bedroom window, squashing a 150-year-old fig tree, and a giant oak was uprooted.
Mrs Papps said they were trying to work out whether the "path of wind" that went through was a tornado.
Nayland Primary School principal Janice Gulbransen said branches had been torn off trees and had damaged property in the school grounds. Poles holding up the shade sails over the playground, which were telephone pole size, had been "ripped off at ground level".
Those areas had been barricaded off for safety, Mrs Gulbransen said.
The thunderstorm shook Craig Iles' timber house in Appleby and electricity surges sent sparks shooting out of power sockets.
"The whole house was shaking," said Mr Iles. "The lights in the lounge popped at about 11pm and sparks came out from the TV plug. I unplugged it, and sparks were shooting a metre out."
He turned off the mains and was worried for his 15-week-old twin girls. "It was real loud. The thunder sounded like it was right outside. I didn't mind but the missus was pretty scared."
He said their computer modem bought two weeks ago was wrecked,.
A lightning strike in the Richmond area at 10.46pm cut the power supply to 3400 customers from lower Richmond through Appleby and Redwoods valley to Mahana and Mapua, Network Tasman chief executive Wayne Mackey said today.
A second strike five minutes later cut supply to 2500 customers from Founders Park north through to the Glen, Hira and Cable Bay.
"These strikes generated high levels of fault current that our sensitive protection devices reacted to and cut the power supply," Mr Mackey said.
No damage was caused to lines and supply was restored in just over 30 minutes to most customers, except in the Redwoods Valley and Rabbit Island areas where power was restored just before 1am.
Mr Mathieson said the storm stretched from coastal Motueka to the interior of the region, and dumped good doses of rain to parched areas. He said the first "real deluge" hit around 10.50pm. It dumped 18mm of rain in the Richmond hills near the top of Hill St and 13mm in Stoke near Broadgreen. Brooklyn, near Riwaka, received 14.4mm of rain.
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