Heavy rain ‘Red’ warning reflects landslip risk: Coromandel Peninsula

MetService has this afternoon issued a ‘Red’ level heavy rain warning for the Coromandel Peninsula.

The decision to issue a Red Warning has been made by MetService, Waikato Regional Council and Thames-Coromandel Civil Defence. A Red Warning is only issued for the most impactful events and in this case has taken into account that the catchment is heavily saturated from unprecedented rainfall.

The warning gives communities time to prepare for the event.

“We are already seeing the impacts of the multi-day severe rainfall events over the past two months, with multiple slips and road closures across the Coromandel Peninsula,” said Regional Flood Coordinator Derek Hartley.

The forecast is for rain to impact the Coromandel Peninsula from the early hours of Wednesday morning and to continue through the day. At this stage, 80 to 120mm of rain is expected about the ranges, with lesser amounts about the coast, and peak rates of 15 to 25mm/h mainly about the ranges.

Mr Hartley said: “Our concern is the additional rainfall forecast has the potential to exacerbate the existing conditions and cause further flooding and slips, as well as debris flow in waterways.

“The impacts from this next weather event could result in even more disruption to people and communities, with prolonged road closures, impacts to infrastructure and even private property.

“It’s incredibly difficult to predict where these impacts might occur. However, if the weather allows it, we’ll be undertaking an aerial survey of areas around the Coromandel Peninsula likely to be of higher risk. We hope to do this on Tuesday morning, but it will be dependent on suitable weather,” Mr Hartley said.

“On board we’ll have geotechnical and river/catchment experts with the skills to assess the condition of land and waterways.”

While not included in the warning, the rain is also expected to spread over other parts of an already sodden Waikato region, including Taupō. Steep areas are particularly at risk of landslips where the ground is saturated.

These weather systems are difficult to predict, and the warning may change, so people are urged to keep up-to-date with the latest MetService forecasts. Mr Hartley warned people to exercise caution and to not enter swollen waterways.

Landslips can happen without warning. People in slip-prone areas need to remain vigilant and contact their local council if required, or in an emergency dial 111.

Find out what to do before, during and after a landslip, here: getready.govt.nz/landslides.