New Zealand – Hundreds Evacuated After Flooding Hits West Coast – 350mm of Rain in 24 Hours

A day of wild weather caused several rivers to overflow in parts of New Zealand’s South Island. Some areas saw over 350 mm of rain in 24 hours. Strong winds brought down trees and power cables.

Around 200 people, many of them tourists, have been evacuated after the Waiho River flooded the town of Franz Josef in Westland district. Several people were evacuated from their homes in Riwaka township in Tasman District after the Riwaka River overflowed.

Tasman District

Nelson and Tasman civil defence officials say that the Riwaka, Takaka and Aorere rivers have overflowed after torrential rainfall in catchment areas.

The worst affected area is the township of Riwaka, flooded by the river of the same name. Local officials estimate that the flow of the river reached around 200 cubic metres per second. In a statement earlier today, Nelson and Tasman civil defence said:

“This flood flow in the Riwaka River would be the second highest since records began in 1982 (210 cumecs was recorded in July 1983), and corresponds to approximately a 1 in 50 year flood event”.

Flooding, fallen trees and landslides in Tasman District have caused over a dozen road closures. A relief centre has been set up at the Motueka Recreation Centre for those displaced.

This is the second time the area has seen severe flooding and torrential rain since early February. Parts of Nelson city and Tasman district were drenched on 17 February this year, with some areas recording over half a metre of rain in 2 days. Between 17 and 18 February, 528 mm of rain was recorded at the Paradise rain gauge in the hills behind Takaka

Franz Josef, Westland District

Late on Wednesday 23 March, 2016, the Waiho River breached its bank. A state of local emergency was declared for Franz Josef in the early hours 24 March 2016 as a result. Westland Civil Defence has issued a boil water notice for the whole of the Franz Josef town water supply area.

Some people in the area have been evacuated as a precaution, with up to 180 people being temporarily displaced. A Red Cross Welfare Centre has been set up in Franz Josef.

Westand Civil Defence said:

“The Wahio River water quickly flooded land around the Mueller Wing of Scenic Circle hotel causing the immediate initial evacuation of 70 people (60 staff and 10 tourists). The water then reached the Top 10 Holiday Park, with 100 tourists being evacuated. At Westwood Lodge 16 were evacuated. Some evacuated people self-drove north out of the flood zone”.

Rainfall

Local civil defence officials say that “over the 24 hours from 9am yesterday 250 to 350mm of rainfall fell across the northwest ranges and Kahurangi National Park area, and 150 to 200mm about the Richmond Ranges”.

At least 5 locations in the area recorded over 250 mm of rainfall in 24 hours between 23 and 24 March, 2016. As with the mid February floods, the rain gauge at Paradise recorded the highest levels, with 376 mm falling in 24 hours. Collingwood recorded 298 mm, Harwoods 267 mm, Canaan 336 mm and Takaka Hill 254 mm.

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Flood summary

Last updated: July 15, 2016
Event
South Island, New Zealand, March 2016
Date
March 23 to March 25, 2016
Type
Inland flood, River flood
Cause
Extreme rainfall
Around 200 people have been evacuated after several rivers overflowed in Westland and Tasman Districts, New Zealand. More than 350mm of rain fell in 24 hours in some areas.

Locations

A - Franz Josef, New Zealand
B - Riwaka, New Zealand

Magnitude

River level
Overflowing
Waiho River, Franz Josef, New Zealand - March 23 to March 24, 2016
River level
Overflowing
Riwaka River, Riwaka, New Zealand - March 23 to March 24, 2016
River level
Overflowing
Takaka River, Harwoods, New Zealand - March 23 to March 24, 2016
River level
Overflowing
Aorere River, Tasman District, New Zealand - March 23 to March 24, 2016
Rainfall level
298 mm in 24 hours
Collingwood - March 23 to March 24, 2016
Rainfall level
376 mm in 24 hours
Paradise - March 23 to March 24, 2016
Rainfall level
267 mm in 24 hours
Harwoods - March 23 to March 24, 2016
Rainfall level
336 mm in 24 hours
Canaan - March 23 to March 24, 2016
Rainfall level
254 mm in 24 hours
Takaka Hill - March 23 to March 24, 2016

Damages

Evacuated
180 people
Franz Josef, New Zealand - March 24, 2016
Evacuated
20 people
Tasman District, New Zealand - March 24, 2016