Thunderstorm watch: 100,000 lightning strikes across the country

Friday, 6 December 2019

It's a stormy weekend ahead, with most of the country expected to see thunderstorms, lightning and rain.

In the past 24-hours, there have been almost 100,000 lightning strikes over New Zealand and surrounding waters, with some of those strikes associated with the severe thunderstorms over Westland, MetService stated.

The South Island's West Coast has been hammered by heavy rain and thunderstorms, causing power outages, slips and road closures.

State Highway 6 remained closed from Hokitika to Makarora, Otago.

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The section of highway from Haast to Makarora was expected to re-open to one lane on Sunday at 10am and close again at 4pm.

Westland District Mayor Bruce Smith said the worst of the weather appeared to be over and it was good news the road would be re-opened from Haast tomorrow.

Slips to the south of Hari Hari near Mt Hercules would take some time to fix, he said.

'It's a significant problem.'

The road closure was very negative for tourism businesses in the region, Smith said.

'It's not just the day or two that it take for them to re-open, it's the loss of confidence that the operators have. Every time something like this happens they are

questioning how viable it is to come this way, where there is always a risk of road closure.'

'The residents are very very resilient. They're West Coasters, and this is not unusual and it's certainly not unusual in spring time.'

Timaru residents captured videos of thunder and lightning overnight. Credit: Alisha Martin

The last time the region was hit by similar weather disruption was in 1988 when the Grey River flooded, Smith said.

'So it's been a while but it's not unusual.'

Smith said the road closures were not preventable.

Lightning and thunder kept many South Canterbury residents awake overnight.

'…it's nature…it's about a bad storm with close to 400 mm [of rainfall] and we've just got a very wet spring.

There's certainly nothing wrong with our roads, our roads are as good as anywhere but when a mountain slides down on a road you've got to clear it.'

A severe thunderstorm warning and a heavy rain warning for parts of the West Coast was still in place.

A state of emergency has also been declared in Timaru after the 'significant' flooding, which was a one in 20 years event.

The national forecaster is warning residents to be aware of torrential rain and hail, which could cause flash flooding and rising streams and rivers.

On Wednesday, more than 2000 sandbags were sent to Queenstown, Wanaka and parts of Central Otago to prepare for possible flooding.

Slips and flooding are causing issues for motorists and authorities on the West Coast of the South Island. Here, the damage to the road at the foot of Mount Hercules, near Whataroa is apparent.

Water was running down streets in Wanaka on Saturday, after heavy rain caused surface flooding, and a handful of roads are closed.

Timaru residents also experienced thunderstorms on Saturday morning. A severe thunderstorm watch was in place on Saturday for the Canterbury High Country and also Nelson ranges.

Heavy rain has caused surface flooding in Wanaka.

In south Canterbury, SH1 was closed after the Rangitata River broke its banks and campers have been told to evacuate. While SH6 on the West Coast was also closed due to multiple slips.

The Arthur's Pass SH73 route between the West Coast and Canterbury was down to a single lane on Saturday afternoon.

Police have also been contacted by residents concerned about the rising water level of the Hokitika River, as well as reports of flooding at the Whataroa Gorge camp ground.

Large volumes of water flow down Rangatata River after heavy rain in the area.

West Coast Civil Defence spokeswoman Erica Andrews said the Westland Emergency Operations Centre was activated.

Christchurch is predicted to have a wet and thundery day on Saturday, which will clear in the evening. A high of 26 degrees Celsius is forecast.

Heavy rain caused a slip near Haast earlier this week.

Dunedin residents can expect some showers throughout the day, with a high of 23C forecast.

MetService meteorologist Andy Best said there were warm, moist winds and unstable weather across many parts of the South Island - the perfect conditions for thunderstorms to form.

The unstable northwest flow would also likely cause thunderstorms to form near Nelson on Saturday, with 25-45mm of rain expected.

But the North Island was also in for some wet and thundery weather on Saturday afternoon.

A severe thunderstorm watch was in place for Northland, Auckland, Great Barrier Island, Coromandel Peninsula, Waikato, Bay of Plenty, Rotorua, Taupō, Gisborne and Hawke's Bay until Saturday evening.

There's a moderate risk of thunderstorms occurring, with 25mm-40mm of rain expected during heavy downpours in Northland. During these thunderstorms, hail was also possible.

Auckland residents can expect a warm, wet day with a high of 26C predicted, while 32C is forecast for Whangarei.

Wellingtonians will have a wet blustery Saturday, with a high of 20C expected.

A strong wind watch was also in place for the capital and Wairarapa until Saturday evening, with norwest winds possibly turning to severe gales.

A moderate risk of thunderstorms was also in place for Taranaki, particularly from Saturday evening.

The rain was set to hang around for many parts of the country on Sunday, especially in the north, with strong winds also expected in Marlborough, Wellington and Wairarapa.

MetService has also warned of more thunderstorms across the country on Sunday.