By Hilary Barry
The volcanic alert at Tongariro National Park remains at level 2, just over 18 hours after Mt Tongariro burst into life.
It was the first time in more than a century the volcano has erupted, throwing rock and ash into the air.
The Ketetahi hut took a direct hit from a boulder that had gone 1km into the air and come back down on one of the mattresses inside. Others hit the water tank and surrounding area.
Nobody was injured in the explosion, but those who live in homes dotted around the base of the mountain were treated to a front-row seat.
Residents describe seeing a yellow glare on the mountain, followed by a huge plume of ash and a dramatic electrical storm.
From the air you could see how the ash had landed, with darker shades of grey covering normally green pasture.
Almost every roof in the settlement at Rangipo was covered in thick ash. But the mountain, hidden under a shroud of cloud, refused to reveal the damage.
Scientists say the blast took them by surprise and lasted only a couple of minutes.
“We have had a small volcanic eruption – hydro, not magmatic,” says volcanologist Brad Scott.
He says there was no warning Mt Tongariro was going to blow, and a further eruption may be on the way.
Dr Thomas Wilson, lecturer in hazards and disaster management at Canterbury University, says activity on the mountain could change quickly.
However, it is difficult to know what will happen next, and although things could get worse, the volcano might settle down completely or small eruptions could continue.
"I can't give you any probabilities on the likelihood of these scenarios," he said, "but we can't rule anything out at this stage."
Only some of the ash settled – most of it remained in the air, disrupting flights across the North Island.
But disruption was nothing compared to what could have happened if Tongariro had erupted on huts full of trampers.
Dr Jan Lindsay, senior lecturer and volcanologist at Auckland University, says it is possible ash may reach Auckland as this has happened in the past.
"It will be interesting to see how the eruption develops - whether it continues for months, or is over already," she said.
"If the former we may see ash reaching Auckland, depending of course on the wind direction."
What could happen next?
- Activity stops
- Small eruptions continue with light ash falling across the North Island
- Larger eruptions with thicker amounts of ash fall across a large area.
3 News/NZN