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Dunedin Flooding: How Does It Match Up With Other Recent Weather Events?
Melanie Earley, Senior journalist
Dunedin has recorded its "wettest day in a century" as rain continues to hit the Otago region - but how does the rainfall compare to other recent flooding events?
A state of emergency has been declared in Dunedin and a red heavy rain warning for North Otago, Dunedin and coastal Clutha is not due to end until 11pm Friday.
It is the region's first red heavy rain warning since MetService introduced its colour-coded severe weather warning system in 2019.
Across the country there have only been 15 red rain warnings issued since then - including during the Canterbury flooding in May 2021, the 2022 flooding in Gisborne and Wairoa, the 2023 Auckland floods and Cyclone Gabrielle.
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According to NIWA, by 9am on Friday, Dunedin had experienced its wettest day in over a century with 130.8mm falling in 24 hours.
Advertisement - scroll to continue readingProvisionally, Dunedin (Musselburgh) has just observed its second-wettest day on record with 130.8 mm from 9:00 am Thursday-9:00 am Friday.
It has been their wettest day in over a century; the last time it was at least this wet in Musselburgh was in April 1923. pic.twitter.com/k7cnzu8Aji
— NIWA Weather (@NiwaWeather) October 3, 2024
Here's how that compares to the largest amounts of 24-hour rainfall in other red rain warning events.
Canterbury Floods, May 2021
The Canterbury floods saw intense rainfall over three days with severe flooding in many areas east of the Eastern foothills.
Flood damage repairs took three years with damage to roads and bridges, flooding homes and farms.
According to NIWA's climate summary at the time, six Canterbury areas had record or near-record high one-day rainfall totals for May.
Winchmore experienced 78mm of rain on 30 May, while Akaroa had 98mm on the same day. Waipara West had 75mm the day before while Lake Tekapo experienced 107mm that day.
Hanmore Forest had 90mm of rain in 24 hours and Ashburton came in at 62mm.
Gisborne and Wairoa Floods, March 2022
In the last week of March 2022, Gisborne and Wairoa were hit by floods which caused extensive damage to the region, including washing out the Tokomaru Bay bridge, isolating communities.
At the time, MetService reported Gisborne was hit with "around three months worth of rain" for the region in just 24 hours.
Between 250 to 300mm of rain was recorded.
Auckland Anniversary Floods, January 2023
Even before the 27 January storm hit Auckland, it had been an unusually wet month - but on that day NIWA recorded there had been 280mm of rain in under 24 hours in the city centre.
The weather caused widespread flooding and damage to Auckland and resulted in the deaths of four men - Dave Young in Onewhero, Daniel Mark Miller and Daniel Newth in Wairau Valley, and Dave Lennard in Remuera.
Many people lost their homes and flood-damaged cars had to be towed out of the city.
An internal review later found MetService's weather modelling systems did not forecast the amount of rainfall or degree of severe flooding caused by the deluge.
The region was then hit by Cyclone Gabrielle only a couple of weeks later.
Cyclone Gabrielle, February 2023
Cyclone Gabrielle battered much of the North Island, claiming the lives of 11 people and causing nearly $13.5b worth of damage.
The heaviest 24-hour rainfall for Northland's Whangarei, was 183.8mm between 8am 12 February to 8am 13 February, MetService said.
While Napier Airport recorded its wettest February day from 8am, 13 February, to 8am 14 February, measuring 175.8mm.
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