Cyclone winds and floods that swept across southeastern Africa affected more than 2.6 million people and could rank as one of the worst weather-related disasters recorded in the southern hemisphere, UN officials have said.

Rapidly rising floodwaters from Cyclone Idai have created an “inland ocean” in Mozambique, prompting fears for the safety of tens of thousands of families as rescue crews struggle to reach remote areas.

The storm surge has killed more than 200 people in Mozambique, Filipe Nyusi, the country’s president said.

At least 400,000 people have been left homeless.

Many more are missing and thousands are considered at immediate risk across Mozambique, Zimbabwe and Malawi.

Cyclone wipes out 90% of city in Mozambique: in pictures Show all 15 1 /15 Cyclone wipes out 90% of city in Mozambique: in pictures Cyclone wipes out 90% of city in Mozambique: in pictures Residents are on a roof surrounded by flooding in Beira, Mozambique AFP/Getty Cyclone wipes out 90% of city in Mozambique: in pictures Chimanimani locals walk near one of the many roads that have been damaged by Cyclone Idai EPA Cyclone wipes out 90% of city in Mozambique: in pictures Praia Nova in Beira, Mozambique that has been devastated in Cyclone Idai EPA Cyclone wipes out 90% of city in Mozambique: in pictures Submerged area of Praia Nova in Beira, Mozambique EPA Cyclone wipes out 90% of city in Mozambique: in pictures Praia Nova in Beira, Mozambique that has been devastated in Cyclone Idai EPA Cyclone wipes out 90% of city in Mozambique: in pictures Locals stand beside a damaged section of road between Beira and Chimoio in Mozambique AFP/Getty Cyclone wipes out 90% of city in Mozambique: in pictures Pylons and telegraph poles amidst the flooded area outside Beira in Mozambique AFP/Getty Cyclone wipes out 90% of city in Mozambique: in pictures Praia Nova in Beira, Mozambique that has been devastated in Cyclone Idai Reuters Cyclone wipes out 90% of city in Mozambique: in pictures Damaged sports arena in the Ponta Gea area of Beira, Mozambique EPA Cyclone wipes out 90% of city in Mozambique: in pictures Submerged area of Bozi in the south of Beira, Mozambique AFP/Getty Cyclone wipes out 90% of city in Mozambique: in pictures A young man sits in front of destroyed settlements in Beira, Mozambique EPA Cyclone wipes out 90% of city in Mozambique: in pictures Residents carry their belongings through a flooded section of Praia Nova in Beira EPA Cyclone wipes out 90% of city in Mozambique: in pictures A man searches through the rubble in Beira, Mozambique EPA Cyclone wipes out 90% of city in Mozambique: in pictures Residents walk through a flooded area of Beira, Mozambique EPA Cyclone wipes out 90% of city in Mozambique: in pictures Locals queue to receive aid during search and rescue operations in the wake of Cyclone Idai in Chimanimani, Zimbabwe AFP/Getty

Emergency workers called it the region’s most destructive flooding in 20 years. Heavy rains are expected to continue through Thursday.

Herve Verhoosel of the World Food Program (WFP), said the crisis ”is getting bigger by the hour”.

Many people were crammed on rooftops and elevated patches of land outside the port city of Beira as the WFP was rescuing as many as possible and airdropped food, water and blankets, he added.

“This is the worst humanitarian crisis in Mozambique’s history,” said Jamie LeSueur, who is leading rescue efforts in Beira for the International Federation of Red Cross and Red Crescent Societies.

Mozambique’s Pungue and Buzi rivers have overflowed, creating “inland oceans extending for miles and miles in all directions,” Mr Verhoosel said. Dams have reached 95 per cent to 100 per cent capacity.

“People visible from the air may be the lucky ones and the top priority now is to rescue as many as possible,” he added.

The full extent of the damage is not known as many areas remain unreachable.

With key roads washed away, aid groups are trying to get badly needed food, medicine and fuel into hard-hit Beira, a city of some 500,000 people, by air and sea.

Some estimates suggested as much as 90 per cent of the city has been wiped out in the disaster.

Cyclone Idai made landfall in Beira, before sweeping across central Mozambique and dropping huge amounts of rain in neighbouring Zimbabwe’s eastern mountains.

That rainfall is now rushing back through Mozambique, further inundating the already flooded countryside.

“It’s dire,” Caroline Haga of the Red Cross said from Beira. “We did an aerial surveillance yesterday and saw people on rooftops and in tree branches.

“The waters are still rising and we are desperately trying to save as many as possible.”

Support free-thinking journalism and attend Independent events

In Zimbabwe, the death toll has risen to 98, the government said. The mountain town of Chimanimani was badly hit. Several roads leading into the town were cut off, with the only access by helicopter.

“We did over 38 burials this morning,” Absolom Makanga, a Salvation Army divisional commander said

“It is difficult. We have to walk long distances because the roads are cut off but also because sometimes the graves are then washed away.”

Malawi’s government has confirmed 56 deaths, three missing and 577 injured in the flooding. Around 11,000 households are thought to have been displaced in the southern district of Nsanje.

Neighbouring Tanzania’s military airlifted some 238 tons of emergency food and medicine to the three countries.

The UN has allocated $20m (£15m) of aid for the cyclone’s victims.

“If the worst fears are realised ... Then we can say that it is one of the worst weather-related disasters, tropical-cyclone-related disasters in the southern hemisphere said Clare Nullis, of the UN World Meteorological Organisation.