Westland's Arahura River flooded more than 1m deep on road where woman swept to her death

At the peak of the West Coast floods, more than a metre of water was swirling down Arahura Valley Rd near where a woman was swept to her death.

The police said Gloria Reardon-Hirst, 66, died after being carried away in the strong-flowing current of surface flooding on the road. It appeared she had got out of the vehicle she was driving and tried to cross the floodwaters on foot.

Garth Bloomfield, co-owner of Blue Spur Farmstay, knew Reardon-Hirst as a neighbour. She had lived at a house several hundred metres away for about a year.

He said her death was a shock to the Arahura Valley community.

The Arahura River flows from the Southern Alps to the Tasman Sea, one catchment to the northeast from the massive Hokitika River and its tributaries.

The Milltown Rd bridge across the Arahura River in Westland, well upstream from where a woman died, had a section wrecked by the flood. Photo / Facebook

Bloomfield said Arahura Valley Rd, in the area where Reardon-Hirst was swept away, was not far above the surface level of the Arahura River in normal flows.

Reardon-Hirst's house - which was not flooded - was one river terrace above the normal flow and Blue Spur Farmstay was one terrace higher again. There was flooding at the entrance to Reardon-Hirst's place.

"The road was shut and it's taken a lot of fences out. There's been at least a metre of water going down the road. It was probably wetter on this side than on the Hokitika side."

"There was 1 metre of water on the road at some stage. I'm not sure that was when she arrived or not. There was a good metre of water running down the paddocks and the road."

Bloomfield said the volume of water he saw coming down the Arahura Valley was the most he had seen in his 15 years living in the area.

A state of emergency was declared in Westland District on Tuesday. The record-setting torrential rain swept away bridges, including on State Highway 6 over the Waiho River near Franz Josef Glacier and the Milltown Rd bridge in the Arahura valley well upstream from the fatality site, and closed other roads with landslips.

Niwa said the rain gauge at the Cropp River waterfall in the Hokitika catchment recorded 1086mm in 48 hours, the highest 48-hour rainfall total on record for New Zealand.