Rivers burst their banks and locals fled their homes as a deluge from Cyclone Gita caused flooding across the Nelson Tasman region last night.
A state of emergency was declared after severe flooding in Takaka and Riwaka.
Daniel and Katie Clark were evacuating with their two children, aged 3 and 18 months.
They said in the 10 years they'd been in Riwaka, this was the worst flooding they'd ever seen.
"We do get floods, but this time it's scary," Katie said.
"It's the highest we've ever seen. It's through our neighbour's house, and not far from going through ours."
Cameron Noble, his wife and their 11-month-old son also left their Riwaka home after the water began to rise. Noble fought back tears as he said he'd feared for his son as the water started to rise.
"It had been fine all day and then it started rising through the floor boards.
"It's just ... it's just a bit scary.
"It's okay though, the parents are in town and we can go and stay with them," Noble said.
"My wife's okay, my kid is okay, we'll be okay."
Evacuation centres were set up in Motueka and Nelson. Many people in Nelson went to the civil defence centre because they simply had nowhere else to go.
Flights were grounded from midday, campsites evacuated, and some main roads closed including the route to Golden Bay.
Accommodation filled up quickly, leaving some people with no option other than the Salvation Army hall on Rutherford St.
Earlier in the day, locals in Nelson were sandbagging their homes. Many along the waterfront were still damaged from Cyclone Fehi at the beginning of the month.
Rosie Musturs said the storm surge from Cyclone Fehi swamped their house and garden, bringing water in through the garage, flooding up to a metre high.
Their emergency supplies had been stored in a large bin at the side of the house, but the power of the water knocked it over and swept the supplies away. This time they'd put in sandbags, nailed wood over doorways, and had their emergency supplies up high.
"We've put in sandbags with rubber underneath, we've constructed a defence on the side of the house, and then around the back we've just blocked off absolutely everything," Musturs said.
"We've got family all around, so we'll all be staying on the phones.
"Last time the emergency supplies floated away, but this time we've got it high up inside the house.
"Lots of water, power packs in case the power goes off. So we feel we can handle anything over the next three days."
Sharlane Evans was also sandbagging her home, wary of the flooding last time that had put sewage through neighbours' homes.
"It's easier to prevent than fix it, especially raw sewage. Raw sewage last time, I really don't want that in my house."
Cyclone Gita is the third severe weather event in two weeks for the Nelson Tasman region.
Cyclone Fehi struck in the beginning of February, and last weekend there was torrential rainfall of 145mm.