Broken power poles and trees blocked the roads and sheets of corrugated iron stripped from homes littered the capital.

“It was a particularly bad night,” Graham Kenna, from the National Emergency Office, told Radio New Zealand. “I’ve been involved in disaster response for 30-plus years and it was the worst situation I’ve been in.”

Even the Tongan Meteorological Service lost its roof, forcing it to hand over the job of issuing warnings about the cyclone to its counterpart in Fiji.

Storm damage closed the international airport, along with the Australian High Commission, which warned its citizens against travelling to the devastated kingdom.

Yet officials said it could have been worse. The storm did not reach a top-of-the-scale Category Five as feared and there were no confirmed deaths as of mid-afternoon on Tuesday.

The howling winds cut power to Tongatapu on Monday evening and peaked in the early hours of Tuesday as fearful residents hunkered down.

Police said more than 3,000 people were sheltering in 41 evacuation centres.

The military helped clear roads at first light, allowing clean-up teams to fan out and assess the extent of the destruction.

“Someone’s roof is in my front garden … some of the old landmark buildings that are 100 years old have been severely damaged by debris,” Kenna said.

In the middle of the storm, phone networks continued to operate and many of the 75,000 people on Tongatapu shared their experiences online.

TVNZ’s Pacific correspondent Barbara Dreaver said the cyclone sounded like “a screaming freight train”.

“Hotel is shaking and can hear screech of metal flying past outside … rain water coming in sideways to second floor room. Heart with those not in solid structure this is bad gita #tonga,” she tweeted.

Lord Fusitu’a, a hereditary peer in Tonga’s parliament, wrote: “I can literally feel my room shaking to the foundations – it’ll be a long night.”

As the cyclone moved out to sea early on Tuesday, he said Nuku’alofa had experienced “a dose of miracle”.

“Astoundingly #TCGita seems to have subsided & we’ve avoided the worst of it,” he wrote on Instagram.

The storm had already created havoc when it slammed into Samoa at the weekend and authorities in Tonga declared a state of emergency before it hit.

While there was widespread flooding, Kenna said the impact of storm surges on the flat terrain of Tongatapu was also less than expected.

“It was very fortunate that the worst of the cyclone came at a dead low tide, so it sort of worked in our favour,” he said.

The storm also passed just south of the capital rather than making a direct hit.

But forecasters warned the threat from Gita was not over and it could still reach Category Five as it heads towards Fiji’s remote and sparsely populated Ono-i-Lau island group early on Wednesday.

Philip Duncan, chief forecaster at New Zealand’s Weather Watch service, said it could then brush Norfolk Island and New Caledonia before dissipating over New Zealand next week.

New Zealand announced NZ$750,000 (US$544,000) in aid and deployed an air force plane to send supplies to Tonga.

“Given the force of this cyclone, all signs point to a lengthy clean-up effort,” Foreign Minister Winston Peters said.