Catastrophic floods caused by torrential rains have forced thousands to flee their homes in Mozambique, with many residents trapped on rooftops amid rising waters, according to aid organisations and witnesses.

More than 620,000 people have been directly impacted by the devastating floods, which have destroyed more than 72,000 homes and severely damaged essential infrastructure including roads, bridges, and healthcare facilities, according to the International Federation of Red Cross and Red Crescent Societies (IFRC), which is providing emergency aid.

“Rains are still expected to continue for the coming days, and the water dams are already at full capacity, so the situation could worsen, placing further people at risk,” IFRC Program and Operations Manager Rachel Fowler told the news agency Reuters from the capital Maputo.

Red Cross volunteers are using small fishing boats in rescue attempts, but access is increasingly challenging, Fowler added. South Africa has deployed an air force helicopter to assist with rescue operations.

Reporting from Manhica district in Maputo province in southern Mozambique, Global News Insight’s Haru Mutasa said residents rescued by the helicopter were being offered medical assistance, food and temporary shelter.

Celeste Maria, a 25-year-old hospital worker, told Reuters her family fled their home in Chokwe in southern Gaza province after authorities issued flood warnings last week.

“Our home is now completely submerged … We left behind neighbours who are now telling us they are sheltering on rooftops as the water continues to rise,” she explained by phone from a resettlement centre.

Aerial images showed expansive flooded areas with only treetops visible above the water.

Officials have not yet released casualty figures from the latest flooding.

Mozambique has experienced repeated weather-related disasters that scientists link to climate change.

Heavy rainfall has also affected parts of South Africa, including the northeast, site of the famous Kruger National Park.

Flood damage to Kruger National Park will require years to repair at a cost of millions of dollars, Minister of Forestry, Fisheries and the Environment Willie Aucamp said in a statement on Thursday.

South African authorities temporarily closed the park last week after several rivers overflowed due to heavy rainfall. The park is a major attraction for both domestic and international tourists.

Fifteen tourist camps remain closed, with some completely inaccessible, Aucamp said. Hundreds were evacuated with no loss of life.

While assessment continues, repair costs are estimated to exceed 500 million rand ($30m).

“The recent floods that we’ve experienced have had a devastating effect on the park,” Aucamp told Reuters. “The indication is that it will take as long as five years to repair all the bridges and roads and other infrastructure.”