The first death from a massive underwater volcanic blast near the Pacific island nation of Tonga has been confirmed, as the extent of the damage remained unknown on January 17.

Tonga remained virtually cut off from the rest of the world, after the eruption crippled communications and stalled emergency relief efforts.

It is two days since the Hunga Tonga-Hunga Ha’apai volcano exploded, cloaking Tonga in a film of ash, triggering a Pacific-wide tsunami and releasing shock waves that wrapped around the entire Earth.

But with phone lines still down and an undersea internet cable cut – and not expected to be repaired for weeks – the true toll of the dual eruption-tsunami disaster is not yet known.

The first known death in Tonga itself was confirmed: that of a British woman swept away by the tsunami. She was identified as Angela Glover, 50, who lived in the Tonga capital with her husband James, Glover’s brother Nick Eleini told British media.

Two women also drowned on January 15 in northern Peru in big waves recorded after the volcanic blast, authorities there said.

Only fragments of information have filtered out via a handful of satellite phones on the islands, home to just over 100,000 people.

In one of the few communications with the outside world, two stranded Mexican marine biologists made a plea for help from their government, using a satellite phone provided by the British embassy to call their family.

“They said they were sheltering in a hotel near the airport and they asked us for help to leave the island,” Amelia Nava, the sister of 34-year-old Leslie Nava, said in Mexico.

Tonga’s worried neighbours are still scrambling to grasp the scale of the damage, which New Zealand’s leader Jacinda Ardern said was believed to be “significant”.

Both Wellington and Canberra scrambled reconnaissance planes on January 17 in an attempt to get a sense of the damage from the air.

And both have put C-130 military transport aircraft on standby to drop emergency supplies or to land if runways are deemed operational and ash clouds allow.

There are initial reports that areas of Tonga’s west coast may have been badly hit.

Australia’s international development minister, Zed Seselja, said a small contingent of Australian police stationed in Tonga had delivered a “pretty concerning” initial evaluation.

They were “able to do an assessment of some of the western beaches area and there was some pretty significant damage to things like roads and some houses,” Seselja said.

“One of the good pieces of news is that I understand the airport has not suffered any significant damage,” he added.

“That will be very, very important as the ash cloud clears and we are able to have flights coming into Tonga for humanitarian purposes.”

Major aid agencies, who would usually rush in to provide emergency humanitarian relief, said they were stuck in a holding pattern, unable to contact local staff.

“From what little updates we have, the scale of the devastation could be immense – especially for outlying islands,” said Katie Greenwood, IFRC’s Pacific Head of Delegation.

Even when relief efforts get under way, they may be complicated by Covid-19 entry restrictions. Tonga only recently reported its first-ever coronavirus case.

France, which has territories in the South Pacific, pledged to help the people of Tonga.