A monster slip blocking Russell Road, northeast of Whangārei, is still moving. Photo: Supplied / Ngātiwai Trust Board
A monster slip blocking the main access route to a series of towns on Northland's east coast is still moving, complicating efforts to reopen the road.
Whangārei District Council infrastructure committee chairman Brad Flower said the landslide that came down on the final day of last week's storm buried Russell Road in mud, trees and boulders weighing up to 100 tonnes.
"We're estimating it's around 100,000 cubic metres of material that's there. Not all of that's come down. There's a portion which has come down on the road, but the bulk of it is actually sitting up above the slip, and that slip is still moving," he said.
"As of yesterday, the cracks are still moving apart. So it's still an active slip."
Flower said even if contractors were able to shift 1000 cubic metres of material a day, and worked every day with no further weather interruptions, it would take 12 weeks to clear the road.
The slip meant communities at Helena Bay, Teal Bay, Ōakura, Punaruku, Bland Bay, Ngaiotonga and Whangaruru had lost their main road connection to Whangārei.
Flower said a "lifeline route" along Kaiikanui Road was open to local residents and essential services, but it was steep, unsealed and at most one-and-a-half car widths wide.
The safest and only fully sealed route to and from the coast was via the Ōpua car ferry to the north.
Some of the boulders blocking Russell Road will have to be broken up using a hydraulic breaker or explosives. Photo: Supplied / Ngātiwai Trust Board
The slip appeared to be only 100 metres wide where it crossed the road, but it "fanned out" further up the hill, so it was significantly wider at the top.
Heavy machinery would have to start by removing loose material from the top.
Flower said Fulton Hogan, the main contractor, had brought in experts who had worked on the Brynderwyn slips of 2023-24.
The company had managed to find a dump site about 2km west of the slip, and the search was continuing for another so debris could be trucked away in both directions.
Simply bulldozing the material into the gully, as many people had suggested, was not possible, Flower said.
"First, we'd get prosecuted for doing that by the regional council. It's not good practice to fill up a gully. Secondly, imagine putting 100,000 cubic metres into the gully, and then we have another weather event, where does that end up? That's a 100,000-cubic-metre wall that heads towards Mōkau and ends up further down, doing damage to homes and farmland and the ocean," he said.
"We really feel for people that are affected by this, who are cut off and can't get in and out, but we've got to make sure it's done properly, it's safe, and it lasts."
Contractors would use a hydraulic rock breaker to deal with the 100-tonne boulder.
If that didn't work, explosives would be used to fracture it.
Flower said it was the only big boulder that could be seen, but he was certain there were more "big floaters" buried under the mud and debris.
Any damage to the road would become apparent only once the slip had been cleared.
The landslide came down near a slip that closed Helena Bay Hill for several months in 2007.
However, Flower said that was an "underslip" where the road itself had fallen away, making it much more difficult to fix.
The 2007 repairs had held up well in last week's storm.
The latest slip was north of Helena Bay Café and Gallery so those businesses were still open and could be accessed from Whangārei.
Meanwhile, Flower said 35 flood-affected homes had so far been assessed by council inspectors.
Five of those had been red-stickered - meaning they were deemed too dangerous to enter - and 10 had been yellow-stickered, with some restrictions on access.
All roads in the district, apart from Russell Road, had reopened.
A few were down to one lane due to washouts or slips, but the council hoped all would be back to two lanes in time for Waitangi Day.
Whangārei Mayor Ken Couper said as of Friday up to 20 people were still staying at three marae after being forced from their homes by last week's storm, down from 90 earlier this week.
Another 30 to 60 people per day were continuing to use local marae for information, support, and facilities such as showers.
Most of the displaced residents were in the Whangaruru area, he said.
About 800 households had so far been contacted by community welfare staff and 500 visits had been completed.
Two more "recovery hub" sessions would be held on Saturday to update residents on storm recovery work, and provide information about the support services available to them.
The sessions would be held at Ōakura Sports Complex, from 10am to 1pm, and at Whananaki Marae, in Whananaki North, from 2pm to 4pm.
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