Draft:2024 Otago floods

In early October 2024, the Otago region of New Zealand's South Island experienced heavy rainfall and significant flooding and landslides. The weather event affected coastal areas in Otago including North Otago, Dunedin, and the Clutha District, which received an estimated two-months worth of rainfall between 2 and 4 October. On 3 October, a state of emergency was declared in Dunedin, with residents in some low-lying suburbs being told to evacuate. By 4 October, the Clutha District had also declared a state of emergency. By 6 October, the state of emergency in Dunedin and Clutha had been lifted due to improving weather conditions and floodwaters subsiding.

Background

TBW

Flood event

In early October 2024, MetService had reported low-pressure system approaching New Zealand from the Tasman Sea, bring warm and humid air across the country. These rain-bearing easterly winds swept into Dunedin, the coastal Clutha District and eastern Otago throughout 3 and 4 October, soaking an already inundated region which had already experienced wet weather. By 3 October 2024, MetService had issued a red severe weather warning for Dunedin, North Otago and the coastal Clutha District, where 150mm of rain was forecast over a 34 hour period. This marked the second red weather warning that the Metservice had issued this year and the 15th red warning issued in New Zealand history. In addition, MetService issued heavy rainfall warnings for the Bay of Plenty and Gisborne District in the North Island.

By 4 October, Emergency Management Otago estimated that Dunedin had received 160mm of rainfall during the 48-hour period leading up to 10:30 am on 4 October. In addition, 180mm of rainfall fell in hill suburbs while the Clutha District experienced 90 mm of rainfall. While the red warning in parts of Otago had initially been extended until 11pm on 4 October, MetSevice subsequently downgraded this warning to a a yellow heavy rain watch until 9am on 5 October. MetService forecast occasional showers in the coastal Otago area for the night of 4 October and the morning of 5 October, with 10-14 mm accumulating in some places. In addition, the yellow heavy rain watch in Clutha was cancelled while the watch for Southland was lifted.

Impact

By 3 October, surface flooding had led to the closure of several roads in the Clutha District including Taieri Ferry Rd, Toko Mouth Rd, and Milton's Back Road. In addition, several roads in the Gore District including MacGibbon Road, Waiarikiki Road and McGregor Road were closed due to flooding. In addition, the Lindis Pass (New Zealand State Highway 8) between Tarras and Omarama was also closed due to snowfall. At 9:30 pm on 3 October, Civil Defence ordered residents of Surrey Street in the South Dunedin suburb of Caversham to evacuate due to flooding. About 100 people were evacuated from their homes overnight and welfare centres were established at the Saint Clair Golf Club and Forsyth Barr Stadium.

By 4 October, the Dunedin suburbs of Tainui, Musselburgh, St Kilda, Green Island, Caversham, Kaikorai Valley, Peninsula Road and the area around Hoopers and Papanui Inlets had reported surface flooding. In addition, parts of the North Otago towns of Waikouaiti and Karitane were also flooded.

Waikouaiti Coast Community Board member Sonya Billyard also reported that Waikouaiti had been cut off due to the closure of parts of New Zealand State Highway 1 and the Coast Road. Slips were also reported near Ravensbourne and Irvine Road in the Otago peninsula stretching from Macandrew Bay to Portobello, disrupting water supplies. Several roads including State Highway 88 between Forsyth Barr Stadium and Port Chalmers and Portobello Road were closed due to flooding.

Evacuations

According to the Otago Daily Times, 60 homes had been evacuated in South Dunedin by 4 October. By 5 October, nine homes in Dunedin had been "red-stickered", rendering them unsafe to leave. By 6 October, the number of "red stickered" homes in Dunedin had risen to 11.

Responses

Local authorities and civil defence

On 3 October, local Civil Defence authorities warned Otago and Southland residents to monitor weather forecasts and prepare for heavy rain by clearing drains and self-evacuating if necessary. The Dunedin City Council (DCC) also dispatched contractors to check the city's stormwater system and encouraged residents to clear drains of leaves and other debris. Mayor of Dunedin Jules Radich also confirmed that the DCC would commence the distribution of sandbags. That same day, the Otago Regional Council's (ORC) general manager of science and resilience Tom Dyer confirmed that the Council was monitoring rivers and streams across the Otago region and had dispatched contractors to clear

In response to heavy rainfall and flooding, the Dunedin City Council and Clutha District Council declared states of emergency in their areas on 3 October By 6 October, boil water notices had been issued in several Dunedin and Clutha suburbs.

Central government

On 5 October, the Ministry of Social Development issued Civil Defence payments to flood-affected residents in Otago including Dunedin and the Clutha District.

References

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