Valley copped 500mm of rain

A109 Light Utility Helicopter flight with mayor Gisborne City from the air in November 2023.

The district had another close call as a subtropical hosing over the past few days pushed the region close to the edge of serious flooding.

Inland hill country, the Raukumara Ranges and East Cape area suffered the heaviest downpours, with one enclosed valley recording over half-a-metre since the rain started.

Gisborne District Council issued a flood warning for the Waipaoa River but it peaked at 6.3 metres on Monday night.

The deluge overloaded the city’s sewerage system and the emergency valves had to be opened to release sewage into the Turanganui River by the Gladstone Road traffic bridge.

The public is advised not to use the rivers or beaches or take seafood until the council gives the all-clear and warning signs are removed.

Rivers everywhere rose. Inland, the Waikohu River reached the 8.3m mark; at Tolaga Bay, the Hikuwai River reached 6.9m; and the Waiapu River rose to 6m.

Waka Kotahi issued road closure warnings for the eastern Bay of Plenty, affecting Gisborne and Coast travellers.

A major landslip on State Highway 2 just west of Opotiki closed the highway, but an awkward detour was available while clearing work continued yesterday.

Another slip closed State Highway 35 from Opotiki to Waihau Bay, affecting East Cape residents, but that has since been cleared.

Slips and land movement are expected over the whole region, with the amount of rain that came down and soils saturated again.

For many areas, it was the heaviest downpour since Cyclone Gabrielle.

The biggest total was 535mm in the steep, enclosed Raparapaririki Stream valley at the head of Tapuaeroa Valley.

On Sunday, the intensity reached over 25mm in one hour.

Nearby Raukumara Station recorded 448mm while the Waikura Valley copped 300mm.

The wider Ruatoria area received around 200mm while inland, the hills from Gisborne to Tolaga Bay had between 100 and 150mm of rain. Further south, amounts were down to between 70mm and 100mm.

The headwaters of the Waipaoa River saw 184mm over the period while the Waimata River and a private gauge at Makaraka both measured 105mm.

MetService yesterday still had an orange heavy rain watch in force, along with a thunderstorm watch.

The concern was for a sting in the tail, with further fronts expected to cross the district.

Further heavy rain was forecast, with downpours up to 25mm to 40mm an hour.

MetService said warnings for severe thunderstorms might be issued for late afternoon and evening.

The unsettled weather is expected to continue into tomorrow.