Despite the road "running like a river", the Takaka Volunteer Fire brigade managed to get tourists stranded by rising waters to safety from the Takaka Valley.
"It has been one hell of a storm," volunteer firefighter and Upper Takaka farmer Nigel Harwood said.
The Nelson and Tasman districts were among seven around the country that declared a state of emergency yesterday as former Cyclone Gita battered the country with heavy rain, high seas and strong winds.
About 5.30pm yesterday the brigade was called about a couple whose car had been flooded in the Takaka Valley.
Slips were blocking State Highway 60 through to Riwaka, and Takaka River had burst its banks and was flowing over the road.
The couple, driving a people-mover, had tried to drive through the torrent but flooded the engine.
"They had been towed by somebody else to higher ground, but by the time we got there the water had risen even further and was starting to surround them.
"We said, 'You guys are going to have to get out of here,' and they jumped in the truck.
"The road was running like a river.
"It was up over the road, about halfway up the truck's wheels."
They continued up the valley to check for stranded motorists and rescued six or seven other people who could not get through the rising waters.
"We found three cars stuck, and one more by itself. They moved their cars to higher ground and jumped in the truck too."
Harwood transported the people back down the valley in the fire engine to the Upper Takaka Country Club for the night.
"Nobody was in real danger, but they could not spend the night on the road," Harwood said.
Nigel's wife Fiona helped out at the country club with the stranded people.
"We had about 30 to 40 people staying there, all different nationalities, including a busload of tourists who had just come out of the Abel Tasman, people who had come through for a day trip," she said.
"We found bedding for everybody and gave them tea and coffee, and fed them a BBQ with meat patties and egg sandwiches."
Traveller Hein Blef of the Netherlands was part of a group who had just finished the Abel Tasman hike when the storm struck.
"We had just got out before the storm but the water taxi was cancelled because of the high sea. A bus picked us up instead, but then couldn't get through because of the slips.
The bus took them back to the country club for the night.
"We were grateful for the Kiwi hospitality. It was really nice.
"We were a bit surprised with the storm, it was heavier than we expected.
"But it is not the worst place to be trapped, here."
Nigel Harwood said the Takaka River last night was flowing the highest he had ever seen.
The Harwoods' river gauge measured more than 900 cubic metres a second last night, the most ever recorded there.
The highest previously was during the 1983 flood, when it reached 689 cubic metres a second.
"I have been at the farm since 2001, and grew up in Takaka so was there for the 1983 flood, and never seen anything like this," Harwood said.
"It has got to be at least a 100-year flow.
"Ironically we only had about 110-120mm fall on the farm, which here on the West Coast we get before breakfast.
"But coming out of the Kahurangi National Park it was absolutely humming."
He had heard of major damage on the other side of Takaka Hill, near Riwaka, where the river had burst its banks.
The slips on SH60 would take at least two days to clear, Harwood said.
People were having to arrange flights to Nelson, or water taxis from Takaka to Kaiteriteri to get out, he said.
Other areas with major damage included Cobb Valley, where a bridge had been taken out.
"The river there was about 10m higher than usual, right where comes out of National Park," Harwood said.
Nelson Tasman Civil Defence and Emergency Management acting public information officer Ali Hamblin told Newstalk ZB the main slips were on the Riwaka side of Takaka Hill.
"The New Zealand Transport Authority is out there assessing by helicopter and will provide an update, but it is looking like it will take several days to clear.
"It is a pretty big job."
Some people were still stuck on Takaka Hill, and police were coordinating how to get them off, she said.
Welfare crews were getting to other people isolated in the storm.
Damage was major in the Riwaka area, and people were assessing the extent of it today.
For those stuck on the other side of Takaka Hill in Golden Bay, food supplies were coming, but people needed to conserve fuel, she said.
There had been sewage overflows at Kaiteriteri and people were asked not to swim there.
In Motueka, people using bores were advised to boil the water before drinking it, because of the risk of contamination.