Highway 25A washed away in deluge

State Highway 25A on the Coromandel Peninsula has completely collapsed near the summit after heavy rain caused widespread slips and damage across the upper North Island. picture supplied credit: Waka Kotahi

UPDATED

The succession of weather-related events hitting the country this summer has led to the cracking, degradation and ultimate collapse of a section of road near the summit of State Highway 25A, effectively cutting off the main Kopu-Hikuai route.

The stretch of highway was closed late last week as heavy rain, now coined an “atmospheric river”, pounded the Coromandel late on Thursday and continued through the weekend. According to a Waka Kotahi spokesperson, SH25A “was closed on Friday 27 (January), following the formation of deep cracks in the road after Ex-Cyclone Hale”.

In a release, Waka Kotahi has advised inspections of State Highway 25A have been carried out to determine “how the remainder of the road has collapsed into the gully, as a result of heavy rain, which continues to fall in the Coromandel region”.

“Waka Kotahi NZ Transport Agency appreciates just how important this highway is to the Coromandel and that the latest photos of the collapse will be disheartening.”

“We expected that the underslip would deteriorate further, given the ongoing weather,” said David Speirs, director of regional relationships for the Waikato and Bay of Plenty, “but it’s still a shock to see the total collapse of a road that is so vital to this community.

“The site is very much active with road material, earth and debris still falling into the gully,” he said.

Waka Kotahi adds it is “working through solutions for a long-term fix”, leaving many Coromandel locals to speculate on social media about the road possibly being out of action for months. Waka Kotahi said “the ability to start physical work will depend on site conditions, which will be assessed this week when the weather allows”.

“The situation is complex due to the geography and amount of road surface and earth lost in the collapse. As soon as the weather allows, the geotechnical assessment will recommence, which will inform the best way to rebuild the road as robustly as possible,” said David Speirs.

“We understand how frustrating the closure is for locals and visitors, and appreciate the need for certainty about how long a rebuild will take.

“Unfortunately, we cannot offer this yet. Please bear with us while we are in the emergency response phase of an evolving situation,” said Speirs.

Other major Coromandel routes were also affected by the rain, with a significant slip recorded at Ruamahunga, forcing the highway to close between Waiomu and Tapu on State Highway 25. SH25 remained closed as of Tuesday, January 31, between Coromandel and Whitianga due to multiple slips on Whangapoua Hill. Waka Kotahi said further slips occurred on the Thames Coast, and said drivers in the area should proceed with a very high level of caution.

MetService had issued a red heavy rain warning for the Coromandel Peninsula for 18 hours from midnight Tuesday, January 31. Waikato Regional Council advised it would be conducting an aerial assessment once they had clear weather to “identify if there are any areas that may be at risk of debris flow”.

“This warning is important as much as it is precautionary,” said Civil Defence controller Garry Towler.

The decision to issue the warning was made by MetService, Waikato Regional Council and Thames-Coromandel Civil Defence.

Waka Kotahi advised against any unnecessary travel to the Coromandel, saying " a significant portion of the peninsula is affected with multiple road closures in place due to slips and flooding. It is a hazardous and evolving situation”.

If drivers need to leave the Coromandel, the routes out are:

• From Whitianga south on SH25 to Waihī, then west using State Highway 2 (SH2). From Waiomu south on SH25, stay on SH25 to Mangatarata, then on to SH2. There are some closures on SH2 currently, check the journey planner and follow signposted detours. UPDATED: Waka Kotahi reported at 4.46pm Tuesday, that due to a large slip, SH2 (Karangahake Gorge) is closed. Avoid this area or delay your journey if possible. The agency says to follow directions of emergency services on site.