The Nelson Tasman region is facing months of work to recover from recent bouts of bad weather. Photo: RNZ/Nathan Mckinnon
Forecasters say more bad weather is brewing which could bring significant rain to parts of the country, including the top of the South towards the end of this month and into early August.
Earth Sciences New Zealand (formerly GNS Science) meteorologist Chris Brandolino said the next seven to 10 days would be dry from tomorrow.
It would bring some short-term respite for those involved in the cleanup in the Nelson Tasman region.
However, there would be "a pivot point" as the end of the month approached and more heavy rain could be on the horizon.
Brandolino said the source centred on the Tropics which has been experiencing a lot of unusually warm water and there was a tilt toward La Niña conditions.
When that happened in the north it resulted in more rain and thunderstorms in Australasia.
"So when these lows come across from Australia or the Tasman Sea there is this source of moisture pooling and waiting, and if that area is active with rain and thunderstorms, that low pressure over the Tasman Sea when it does form, it can tap into that moisture over the Coral Sea, over Papua New Guinea, over the West Pacific and the Tropics and siphon that down."
That is what the top regions of the South Island have been experiencing in the last few weeks, Brandolino said.
"It is a river in the sky that's able to leverage that moisture and turn it into rain."
It would take a break but in about 10 days the weather would change again.
"That's the concern - there could be these areas of heavy rain again ... those are the themes that are emerging for very late this month and as we work into the first week of August."
An example of some of the widespread damage to roads and infrastructure in the Nelson Tasman areas. Photo: Supplied/ Nick Smith
Volunteers pitch in
An army of volunteers has swung into action in the Nelson Tasman region to help flood-affected farmers and orchardists with the massive cleanup ahead.
It comes as the government announces a $600,000 support package for farmers, growers and foresters across the battered district.
The chairperson of the Top of the South Rural Support Trust Richard Kempthorne told Morning Report the funding was "great news" and "very helpful".
He expected there would be a lot of requests to the Mayoral Relief Fund, which will receive the largest portion, for things that weren't covered by insurance.
As a former mayor of Tasman District, he had seen many adverse weather events.
"This surpasses all of them by quite a chunk. ... It's just enormous, you cannot plan for it."
The cleanup could be "swamping and daunting" and he advised people to try and take it one step at a time to avoid being overwhelmed.
Farmers and growers should ask for help if they needed it, Kempthorne said.
Silt, stones and debris would need to be removed by heavy machinery while the standing up of fences would also be a priority.
There was a lot of thought going into what needed to happen in the river system and stopbanks in the longterm, Kempthorne said.
