Driving in icy or snowy conditions? What’s your plan?


More than 150 vehicles had to wait in freezing conditions in the Tongariro National Park this time last week after truck crashes and snow and ice forced the closure of highways in the Central Plateau.

With freezing temperatures and more snow forecast for the region from tonight – here’s how NOT to spend a very cold night in your vehicle…

“The message is, check the forecast, check the Waka Kotahi Journey Planner. If it’s going to be under 4 degrees, consider whether you really need to drive – or can you delay your trip? And if you’re out there go slow, heed warnings and follow our contractor’s advice on the ground,” says Cara Lauder, System Manager for Waka Kotahi in the Waikato.

“Some drivers are not making good decisions. They’re not taking notice of warnings. They’re not driving to the conditions. They’re going too fast and taking risks. And a crash is extremely disruptive – not to mention dangerous at this time of year. Once traffic is stopped, it can get snowed in,” says Ms Lauder.

Last week freezing conditions saw the closure of SH1 through the Desert Road, between Taihape and Waiouru, SH4 from Taumarunui to the Tongariro National Park and SH47 from the National Park to Turangi.

At least 100 trucks and more than 50 cars were stuck or parked up in Waiouru or National Park due to crashed trucks and dangerous conditions forcing the road closures. And that’s a conservative estimate.

“Waka Kotahi issues advice about potential closures and winter conditions and puts notifications on roadside digital signs. It goes to show how important it is to listen to this advice.

“Pack warm clothes, blankets, food and water if you’re going to drive through this region at this time of year. Conditions can worsen at little notice, or a crash can block the road. It gets very cold very quickly once the engine cuts. If you’re trapped through the night – are you prepared for that?” asks Ms Lauder.

Last week Waka Kotahi contractors, Downer, rescued a family travelling together in 3 vehicles which got stuck on the Desert Road. Contractors’ first priority was moving crashed trucks so they could start ploughing and de-icing. The 6 adults and 12 children were travelling in vehicles without chains and had a cold wait.

“That family was lucky. The Downer crew knew they were there and gave them hot pies. Once it was safe to do so, they were escorted out.

“Crashes are difficult in this region as even heavy tow trucks may not be able to reach a crashed vehicle in the wintery conditions. If maintenance trucks are also involved in a rescue, it diverts resources away from re-opening the road,” Ms Lauder says.

Waka Kotahi and our contractors prepare for these situations by monitoring the conditions around the Tongariro National Park with the help of weather stations and a forecast tool called Metconnect that predicts temperature, wind, rain, snow and ice and helps inform if or when highways may close and how many roading crews are needed to keep highways safe.

“There are a lot of logistics to plan. Depending on the severity of the forecast, our contractors may send as many as 13 crews out. Tonight, the plan is to send seven trucks to do around the clock shifts covering the Desert Road and the route around the mountains via National Park.

“Contractors use snow ploughs and brooms to remove the snow. They also spray calcium magnesium acetate (CMA) to stop ice from bonding to the road surface and apply grit for traction. We go through around 80 tonnes of CMA each year in this region alone.

“An isolated cold snap can create a very icy road in spots. And bridges can be even more dangerous, because while the ground has built thermal capacity (it holds warmth) bridges don’t have that nice insulating earth below. So bridges can freeze up on their own, while the surrounding road is fine. Places like the Makatote viaduct can be really gnarly, while the rest of the road is ok,” Ms Lauder says.

The current forecast shows light snow flurries from midnight tonight and throughout the morning, which may close the Desert Road. Heavier snow is forecasted again for Friday morning.

“Stay home if you don’t need to travel. If you do – be prepared. Driving to the conditions means being very careful about your speed and if you see a vehicle that has skidded or crashed consider whether or not it is safe to pass.

“Assess the conditions when you reach Waiouru, Turangi or the National Park and consider whether it is safe to continue and if not either find somewhere safe to wait or consider an alternate route.

“Waka Kotahi and our contractors are doing what we can to keep you safe – the rest is up to you.”

Check our website for more tips on winter driving.

Winter driving

And watch these handy videos:

Winter driving summary(external link)

How we respond(external link)

How to stay safe(external link)