Top End residents are in cleanup mode after a night of damaging winds and heavy rain from Tropical Cyclone Fina.

Arriving as a category 3 system, Fina brought destructive winds and heavy downpours to remote Tiwi Islands communities, then Darwin and surrounds on Saturday and into Sunday.

On Sunday afternoon the cyclone intensified into a category 4 storm as it moved south-west towards the northeast Kimberley coast, but was expected to weaken quickly on Monday as it moved on.

With top gusts of 195km/h and sustained winds of 140km/h near the centre of the system, Fina tore down trees, damaged houses and cut power in many places across Darwin and surrounding areas. It also brought torrential rain, with 168.6mm falling at Darwin airport in the 24 hours to 9am Sunday.

The storm was the strongest cyclone to approach the Northern Territory capital since Cyclone Tracy devastated the city in 1974. As of Sunday morning, there were no reports of serious injuries but nearly 19,500 homes and businesses were left without power, and phone and internet services were offline.

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Households in and around Darwin, where gusts reached 107km/h, were asked by emergency authorities to stay in their homes or emergency shelters. The warning was still in place on Sunday morning, but by the afternoon residents were advised they could leave home for essential purposes.

As well as strong wind gusts, Fina also brought torrential rain, with 168.6mm falling at Darwin airport in the 24 hours to 9am Sunday. Photograph: (A)manda Parkinson/The Guardian

Saturday was a noisy and in many cases sleepless night for Darwin residents as high winds rattled, banged and shook everything in their path, with sweeping sheets of rain on the streets.

Emergency shelters were open in Darwin, nearby Palmerston and adjacent rural areas, with people urged to bring their own bedding and food.

Around 7am on Sunday, people began emerging from their homes, and authorities began a cleanup survey. Toppled trees in Darwin had damaged fences, powerlines and pavements.

A veteran of Territory cyclones, Kent Pedersen, said the damage around his home was the worst since he lived through Cyclone Tracy in 1974.

Kent Pedersen is a veteran of NT cyclones and remembers the damage done by Tracy in 1974. Photograph: (A)manda Parkinson/The Guardian

“It probably is the worst since Tracy, it’s certainly caused a bit of damage,” he said.

“I didn’t have so much clean up after [cyclone] Marcus [in 2018] and trees have come down in just about every yard, there is even a tree on a roof over there.”

Part of a ceiling at the Royal Darwin hospital collapsed on Saturday but no one was hurt, Emma Carter of NT police told ABC Radio Darwin. The hospital was already placed on code brown amid ongoing staff shortages, and was open only to emergencies, with all other presentations being redirected.

The NT chief minister, Lia Finocchiaro, told ABC radio that no patients were impacted by the collapse, and at a press conference on Sunday afternoon said the hospital had returned to “business as usual”.

Finocchiaro said preparedness meant there had been “minimal impact” from the storm, with the greatest brunt felt by the community of Wurrumiyanga, on the southern coast of Bathurst Island.

She confirmed that around 19,500 homes and businesses lost power in the 24 hours to Sunday afternoon, and that crews were still working to assess damage and restore power as soon as possible. School principals were asked to visit their schools to see if a safe Monday return for students would be possible.

PowerWater reported power outages across Darwin and coastal areas, and said in a statement its crews had started damage assessment and would work to restore power “as soon as it is safe to do so”.

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The Optus general manager for the Northern Territory, Dave Morissey, told the ABC on Sunday morning that 15 mobile sites were offline, with technicians working on getting them back online, and eight mobile sites were running on generators.

Telstra was also reporting widespread outages affecting some mobile, NBN and landline services in the NT, with some mobile towers expected to be out until Monday and many internet and phone services in Darwin estimated to be out of action until Tuesday evening.

On Nitsa Kotis’s street a 10m palm tree fell – away from homes – onto power lines, blocking the road and cutting power.

“I haven’t even been out the back of my place yet to see the damage, I’ve been too busy socialising with the neighbours,” Kotis told Guardian Australia.

Neighbours spilled out onto the street on Saturday morning to inspect the damage, some charging phones and devices from their car batteries, others just milling over their nights.

A palm tree came down on Nitsa Kotis’s street in Darwin’s north. Photograph: (A)manda Parkinson/The Guardian

“I went to my daughter’s house in Muir Head – it was loud, but this morning out there it was like there was no cyclone,” one resident said.

Cyclone Fina also stirred up a rare swell on Darwin beaches.

Despite the crocs and stingers, some surfers braved the conditions to catch a wave.

Brad Cosway was out with his friend Craig Dawson on Sunday for a kite surf at Windsurfers Corner in Nightcliff.

“I don’t want to surf with the crocs, but they aren’t feeding in the saltwater,” he said.

“Plenty of these guys have been out surfing here for 30 years and no one has ever been taken.”

Residents watch large swell off Darwin after Cyclone Fina. Photograph: (A)manda Parkinson/The Guardian