Acid rain from a large volcanic eruption in Tonga continues to threaten water tanks, and ash threatens air quality as huge plumes of gas and dust are thrust into the air.
Hunga Tonga and Hunga Ha'apai are sister volcanic islands in Tonga, with an underwater volcano linking them underwater. Photo: NASA
Tonga's head geologist Taaniela Kula told RNZ Pacific the "huge" eruption began on Monday morning, and by the afternoon ash had dusted the whole of Tonga.
He said ash clouds had since drifted north creating a spectacular sight, and leading to warnings.
"This morning it's still continuing to emit gas and vapour into the atmosphere. This morning you can still see the white clouds, it is probably about 16km high."
He said there is no knowing for certain when the volcano will settle, but expects it to continue for at least another week.
"So if there is any rainfall associated with the eruption they stay indoors and ...wear masks."
Matangi Tonga reported the eruption was at Hunga Ha'apai island, but a bright white gas cloud could be seen from Tonga's capital Nuku'alofa, 65km north, and bursts of lightening played through the cloud on Tuesday evening.
People in Tonga were last night told to protect water tanks from possible acidic rainfall, until the eruption ends.
Tonga Geological Services said residents should remove guttering systems from rainwater tank storage until the eruption finishes. These should not be reinstalled until after the next rainfall, to reduce the risk of contamination.
Symptoms of exposure to acid rain are itchiness and skin irritation, and blurry discoloured vision. If skin or eyes are exposed to acid rain people should see a doctor.
RNZ Pacific spoke to people in Tonga who said the eruption cloud has been dominating the horizon.
"[We were] having fun and swimming in the ocean and we saw the cloud, it was strange, but it was beautiful," said one woman.
"It sounds like a thunderstorm, and it kept going on, it sounded like an explosive to me," another said.
Kula said people are still going on with their preparations for christmas; "streets are still queued with vehicles and people are still doing their shopping"
Nuku'alofa resident Sarah Tu'uta was on a family camping trip in Nuku'alofa when the eruption began. Even 65km away she said the clouds are still a real spectacle and now the centre of conversation.
"Islanders - it's tradition, that when something like that happens we see it as some kind of blessing or curse."
A little further away on Vava'u island Aunofo Havea, a well known voyager, mother and passionate environmental leader in Tonga said her entire village had been rattled by the blast.
While some people see the event as a Christmas gift, and a part of the holiday celebrations others are scared, she said.
Air New Zealand cancelled a flight from Auckland to Tonga that was due to fly yesterday, because of concerns about the ash cloud.
The flight included the funeral cortege for Tonga's Deputy Prime Minister, the late Lord Ma'afu. Matangi Tonga said the funeral programme was postponed as a result.
The flight disruptions are ongoing, with all Air New Zealand repatriation flights halted for the coming days.
In 2015, Tongan government officials said eruptions at Hunga Ha'apai had formed a new island more than a kilometre long, joined to the existing island. It has reportedly become a home for plants and birds.
Kula believes the latest eruption is due to a blocked vent: "to breath out, trying to breath out to exhaust the heat and magma that has been brewing underneath it, yeah nature is just doing its thing."