The destruction caused by Cyclone Kenneth, the strongest storm on record to hit Mozambique, may require another massive aid effort in a country still reeling from the year’s first tropical cyclone, the UN has said.

With high winds and torrential rain, Kenneth made landfall in the country’s north on Thursday night, five weeks after Cyclone Idai devastated its centre.

About 80% of homes were destroyed or partially destroyed in Macomia district, home to more than 90,000 people, according to Unicef. Churches, banks and petrol stations sustained serious damage, with trees flattened. Many roofs were ripped off in adjacent Ibo, with families reportedly left with no food or shelter. One person was killed in the city of Pemba.

Surpassing both Idai and the 2000 cyclone that had been the strongest to date, Kenneth hit Cabo Delgado province with winds of 140mph (225km/h), but heavy rain is expected to cause the most damage.

Information was still trickling out of affected areas on Friday afternoon, but the impact of so much water is expected to escalate over the next few days: river flows will peak around Monday, according to the UN’s emergency agency.

“The Mozambican people know how to respond to disasters like this,” the country’s president, Filipe Nyusi, said in a televised address.

However, with short-term effects including severe flooding, landslides and power cuts, and destroyed homes and harvests in the long term, Mozambique, one of the world’s poorest countries, will struggle to cope.

“Cyclone Kenneth may require a major new humanitarian operation at the same time that the ongoing Cyclone Idai response targeting 3 million people in three countries remains critically underfunded,” said Mark Lowcock, the UN humanitarian affairs and emergency relief coordinator.

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“The families whose lives have been turned upside down by these climate-related disasters urgently need the generosity of the international community to survive over the coming months.”

Forecasters at Météo-France warned Kenneth could bring waves five metres (16ft) higher than usual. Anabela Moreira, who owns a lodge on Wimby beach in Pemba, told AFP: “I’ve never seen anything like it in my 15 years in Pemba.”

After forming off Madagascar’s coast earlier this week, Kenneth passed to the north of the island nation of Comoros on Wednesday night, killing three people and causing widespread damage to homes and infrastructure.

The National Institute of Disaster Management said it would relocate rescue equipment including boats and helicopters from Beira, which was devastated by Idai.

Meteorologists said Kenneth, which was a category 4 hurricane on Wednesday night, was an “anomaly”.

“There’s never been two storms this strong hit in the same year, let alone within five weeks of each other in Mozambique,” said Eric Holthaus, a meteorologist who has worked in east Africa and was watching the cyclone’s path closely.

Holthaus said there was probably a “blocking pattern” in the upper atmosphere that prevented Kenneth from dissipating inland or escaping to the south, so it would most likely sit around 100km (60 miles) inland, attracting more moisture from the Indian Ocean.

“Nothing like this has happened in this region, and rarely happens anywhere in the world, where a cyclone of this strength stalls for this many days. So the kind of rainfall totals that the models are showing for Kenneth are really extreme in the global context,” he said.

There is evidence, however, that blocking patterns such as the one that makes Kenneth so intense are getting stronger with climate change, he added. The rainfall, which could reach 750mm in some areas, will be catastrophic for the people of northern Mozambique.

“We have very strong evidence that everywhere in the world, rainfall is getting more intense,” Holthaus said.

“We can directly link Kenneth with climate change for that reason. Not only is this an extremely intense rainfall event, globally, but it’s being made worse because of climate change.”

Facebook Twitter Pinterest A destroyed house in the Macomia district of Mozambique. Photograph: Nour Hemici/AFP/Getty Images

Hundreds of humanitarian workers are in Mozambique in the wake of Idai, and so the rescue and aid effort is expected to move faster than it did five weeks ago.

The increased threat of diseases such as cholera and malaria, as well as the availability of food, are major long-term worries that communities affected by both Kenneth and Idai face. Kenneth has hit at the peak of harvest season, meaning a possible six-month period without food.

“It’s not just the immediate effects of someone losing their home, it’s also the longer-term effects of food price increases and lack of a harvest for farmers,” the Red Cross’s Matthew Carter said. “What are these people going to be eating for the next three to six months?”

The Cabo Delgado region of northern Mozambique is not as highly populated as the area surrounding Beira, and the main coastal city, Pemba, is not expected to take a direct hit, so there may be fewer people affected than by Idai. But the country is struggling to deal with the after-effects of the first cyclone and has little capacity to tackle a new disaster.

Mozambique has had to take out a $118m (£91m) loan from the International Monetary Fund in the wake of Idai, something debt relief campaigners have called a “shocking indictment” of the international community, saying impoverished countries should be given emergency grants rather than having to borrow more money.