A hydroelectric dam has collapsed in southern Brazil after days of heavy rains that triggered massive flooding, killing more than 30 people.

Officials say another 60 people are missing in Rio Grande do Sul state.

About 15,000 residents have fled their homes since Saturday. At least 500,000 people are without power and clean water across the state.

The burst dam triggered a two-metre (6.6ft) wave, causing panic and further damage in the already flooded areas.

The dam is located between the municipality of Cotiporã and the city of Bento Gonçalves.

The death toll keeps climbing from continuous rains in Brazil's southern state of Rio Grande do Sul. At least 58 people have been killed, while another 67 remain missing according to the state's civil defense agency. The rains have triggered the worst floods in more than 80 years.

Rescuers rushed to evacuate people stranded by devastating floods across the southern Brazilian state of Rio Grande do Sul on Tuesday, with 90 reported dead and desperate survivors seeking food and basic supplies.

On the outskirts of Eldorado do Sul, 17 kilometers (10.5 miles) from the state capital of Porto Alegre, many people who left their homes were sleeping on the roadside and told Reuters they were going hungry. Entire families were leaving on foot, carrying belongings in backpacks and shopping carts.

"We've been without food for three days and we've only just got this blanket. I'm with people I don't even know, I don't know where my family is," said a young man who gave his name as Ricardo Junior.

The flooding has hampered rescue efforts, with dozens of people still waiting to be evacuated by boat or helicopter from stricken homes. Small boats crisscrossed the flooded town searching for survivors.

The state's Civil Defense agency said the death toll has risen to 90 with another four deaths being investigated, while 131 people are still unaccounted for and 155,000 are homeless.

Heavy rains that began last week have caused rivers to flood, inundating whole towns and destroying roads and bridges.

In Porto Alegre, a city of 1.3 million inhabitants on the Guaiba river, downtown streets were under water.

Porto Alegre residents faced empty supermarket shelves and closed gas stations, with shops rationing sales of mineral water. The city distributed water in trucks to hospitals and shelters.

The floods have also impacted water and electricity services, with more than 1.4 million affected overall, according to Brazil's Civil Defense.

The first days of Haiti's rainy season continue to prove destructive and deadly for the country's vulnerable population. The death toll from heavy rains has risen to 17, while the number of homes flooded has doubled to more than 4,000, the country's Civil Protection authorities said.

Most of the destruction has occurred in the northern region of the country in Haiti's second largest city, Cap-Haïtien, the office said in its most recent update on the weather-related disaster.

The report shows that in addition to the loss of lives, more than 4,910 homes have been flooded while at least 40 homes have been either been damaged or destroyed during the rains.