(Bloomberg) -- Catastrophic floods continue to paralyze the southern Brazilian state of Rio Grande do Sul, with four-fifths of the state — home to 11 million people — affected following torrential rainfall. And more rain is on the way, complicating recovery efforts. 

As of Tuesday afternoon, 95 people had died, 131 were missing and 159,000 had been displaced, the state government said, while 1.5 million residents have been impacted in some way by the disaster. 

Many roads around the state are impassable, hampering access to smaller towns and cities. Authorities are using aircraft to distribute food and medical supplies. 

Water utility Corsan said one-fifth of its millions of customers in Rio Grande do Sul are without running water. Power and phone and internet services are down in dozens of municipalities. 

Porto Alegre, the state’s capital and its largest city, was swamped by the overflow of Lake Guaíba, which surged to record levels more than 2 meters (about 6.6 feet) above its normal height. The city has ordered water rationing. 

Porto Alegre’s Salgado Filho International Airport, which usually sees between 120 and 140 flights daily, has been closed since May 3. There is “no forecast of resumption of operations,” according to the company that runs the airport. 

Because the floodwaters haven’t yet subsided, it’s impossible to assess the full impact of the flooding and the funds that will be needed for recovery and rebuilding, said Brazil’s President Luiz Inácio Lula da Silva, who has visited the state with members of his cabinet. 

“The initial difficulty is that no mayor, nor the [state’s] governor, is aware of the damage that has been done,” he said Tuesday. The situation will only become clear “when the water goes down and we see what actually happened.”

Brazil’s Planning Minister Simone Tebet said the government will offer cheap credit and aid to families and businesses to help them rebuild, and that it will seek to provide debt relief to the government of Rio Grande do Sul to facilitate the reconstruction of roads and infrastructure. 

Eduardo Leite, governor of Rio Grande do Sul, warned on Tuesday evening that more danger lies ahead. A mass of cold air is expected to bring new storms, he said. Temperatures are likely to plummet and heavy rain will return to parts of the state later in the week. 

“It isn’t time to return home. The projection is that the rains can generate strong floods,” Leite said at a press conference. 

Army General Hertz Pires do Nascimento said he is particularly concerned about the welfare of residents of Jaguarão, Rio Grande and Pelotas municipalities, with more rain predicted, and that helicopter rescues may be necessary there.  

Rio Grande do Sul is a rainy part of the world, and several factors likely contributed to the severity of the floods. 

The recent intense rains resulted from an atmospheric blockage in the central region of Brazil and a mass of polar air that came from Argentina and Uruguay, in addition to the El Ninõ phenomenon, said Marco Antonio dos Santos, an agrometeorologist at Rural Clima, a forecasting company.

El Niño is what meteorologists call the occasional warming of the eastern equatorial Pacific that has global weather consequences. When those conditions are in place — as they have been since last June — southern and southwestern Brazil can see higher temperatures and more intense rainfall. 

But the timing of this deluge was unusual, said Andrew Kruczkiewicz, a science adviser to the Red Cross Red Crescent Climate Centre and a senior staff associate at Columbia University’s climate school. El Niño is most likely to intensify storms in the region from September to January. 

“In areas where we have rainfall every month, or let’s say year-round, the El Niño teleconnection is a bit more complicated to unpack,” he said. 

Climate change is also likely to have had some influence. The atmosphere has warmed about 1.3 degrees Celsius since pre-industrial times. As air heats up, the amount of water vapor it can hold also rises, about 7% more water for every degree. That means higher rainfall in many places. 

El Niño was recently found to have contributed to low water levels in the Panama Canal and, in combination with climate change, to have worsened catastrophic flooding in Dubai and the United Arab Emirates. 

While El Niño and planetary warming are both central to understanding the flooding, “first and foremost is climate change,” said Michael McPhaden, a senior scientist at the US National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory. 

“Humans are dumping more and more heat-trapping gases into the atmosphere,” McPhaden said. “And this is leading to not only rising global temperatures, but also more extreme weather events, more extreme rainfalls, more extreme droughts.” 

Untangling the major influences on the Rio Grande do Sul floods will take some time, as experts in climate attribution evaluate the disaster. Kruczkiewiecz said he’ll be trying to better understand how much of the flooding in Porto Alegre came from urban rainfall, and how much from river flooding that occurred tens or hundreds of miles upstream. 

“We’re seeing more situations where we’re having combined, different types of floods happening at the same time,” he said. He called this “an increasing concern,” particularly for growing metropolitan areas such as greater Porto Alegre. 

On Tuesday evening, Leite said the state government is beginning to design a housing plan to shelter families who have lost everything. The state has asked the federal government to lend national security personnel and vehicles to address an outbreak of looting and other crimes. 

Whenever the immediate crisis dissipates, officials will also look back to see how emergency systems might be improved to minimize losses when rains come again. 

(Updates in ninth paragraph with comments from Simone Tebet.)

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