After decades of relatively calm weather, Te Tauihu has been hit with a series of significant events which have each left part or all of the region reeling.
From Golden Bay to Marlborough, fires to floods, the unpredictability and frequency of many of those events make it difficult to prepare for what might come next.
A brief report on the extreme weather in the Tasman District prepared by the Tasman District Council’s flood warning team (Martin Doyle, Matt McLarin and Matt Ogden) recapped just over a decade’s worth of significant storms – six in total.
First in 2010 there was “massive flooding” in Golden Bay and surrounding areas, particularly the Aorere Valley, and south through Murchison down the West Coast. Over 35mm of rain was recorded per hour for five hours.
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Then a year later the 2011 storm hit both Tasman and Nelson – with over 600mm of rain recorded in 48 hours in lowland Tākaka, breaking long-term records. One farmer was swept out the door and washed up hundreds of metres away – suffering only a broken finger despite it all.
Rural areas near Nelson, including Cable Bay, were completely cut off by road.
The next extreme weather to hit the entire region (not including a $40+ million flash flood hitting Richmond and the Stoke foothills in 2013) was in 2018, with the combined force of two ex-tropical cyclones one after another – Fehi, which caused storm-surges inundating large stretches of coastline leading to an almost $40 million in insurance claims, and about three weeks later the somehow even more destructive Gita.
When it wasn’t raining, it was tinder-dry – with a hot, dry summer in 2019 helping spark a massive fire across Pigeon Valley in Tasman and leading to the evacuation of the entire town of Wakefield.
Now, the region is recovering from another devastating weather event.
Three waves of heavy rain over about four and a half days hit Golden Bay again, but was most concentrated in Nelson and eastwards into Marlborough.
Two locations recorded over 1 metre of rain, which fell onto already saturated earth thanks to a long lead-up of lighter rain before the atmospheric river hit.
Residents around the region have been cut off, evacuated from their homes unable to return, or otherwise left to pick up the pieces.
As usual, both the Nelson City Council and the Tasman District Council joined forces to manage the emergency response, but now the regions, and they mayors, are starting to reckon with the recovery.
Nelson Mayor Rachel Reese said, unlike the highly predictable Fehi and Gita, the predictions for the atmospheric river of rain were less precise due to the nature of ex-tropical cyclones.
“Nelson wasn’t in the red alert, we were more concerned about other areas,” she said.
“In Golden Bay we had staff to support for what we thought could have been a big event for Golden Bay – in fact it did something quite different.”
Instead of hitting mostly out towards Golden Bay, the storm hit somewhere unexpected – in the Maitai river catchment, where it got “stuck”. Reese said the region relied on MetService rain radars in Wellington and Christchurch, and requests had been made to have a radar in the Nelson region to increase coverage in the area.
“The point at which the intensity of the rain hit, and speed which we had to deal with floodwaters, it was not what we were expecting,” she said.
“Councils and emergency management had to mobilise literally within minutes. Nile St residents were watching and thought ‘we’ve got to go’. Some were literally running from the floodwaters.”
She said on the one hand, having the floods hit Nelson as much as or worse than the neighbouring Tasman District like the last few was no different as a mayor, since it was always a team effort regardless of where in either region the disasters struck – but on the other, it was both literally and figuratively much closer to home.
“Most of the places I’ll go to, most of the people, I know where they work or where their kids go to school – you do really feel it. You do have really close relationships with your community. You’re just looking at the scale of it, what’s been damaged, but you’re really focused on the people.”
Over 1000 people were evacuated over the course of the disaster, with hundreds of homes damaged – some likely beyond repair. Though the damage was largely concentrated in Nelson, dozens of homes in Tasman were also damaged and slips have disrupted transport networks across the district.
Tasman Mayor Tim King said that damage was largely concentrated in Golden Bay, with bridges and roads taken out, but there had been flooding or slips in Richmond and the Waimea plains as well, and “very big, challenging slips” as far south as Murchison.
He said emergency responses always needed “a certain number” of people responding – staff from either council, and this time around people from the National Emergency Management Agency – but the real question was the long tail of recovery.
“The recovery particularly in Nelson – a lot of that land instability will be a long-term case,” he said.
“In [Tasman’s] case it’s probably more the roads, though four houses were red-stickered. Birds Hill is an ongoing challenge, and was before this event. It highlights the vulnerabilities that the whole transport network has – both into and around the region.”
He said the relative frequency of extreme weather events was “a really interesting discussion”, as intensity and frequency seemed to ramp up after a roughly 30-year period of comparatively “benign climate” in the region.
“Prior to the 1980s there were very significant fires, floods, and storms,” he said. “We’ve been through a period of very few [extreme weather events], and then had 10 years where we’ve had a lot. Then there’s also the aspect that, because our population has grown so much … even the same event that took place in the 80s would have a much greater impact now.
“We’ve had a bit of a run of these things … There’s no predetermining when they’ll come – it could be next year or not for another decade.”