Storms last week dumped a month's worth of rain on the area in just six days.
|Lula da Silva announced emergency aid and pledged more funding for reconstruction [AFP]
In one farming village in Alagoas state local officials said almost the entire population of about 60 people had survived by clinging to two 20-metre-tall jack fruit trees for nearly 24 hours.
"It was a true miracle," Adriano de Araujo Jorge, the president of the state's environmental agency, said.
"The jack fruit trees are strong … most of the surrounding trees had fallen."
Al Jazeera's Gabriel Elizondo reporting from the town of Santana do Mundau said that every government service in the town had collapsed.
Hospitals in the town were destroyed by raging torrents of flood water and many people had to be airlifted to other areas to receive treatment.
"It is just incredible what people here are trying to salvage at this point," Elizondo said..
"This is by far the worst we've seen than any of the other cities we've arrived in so far.
"This entire town is destroyed, whereas in some of the other cities it is just the areas near the river."
The government has announced $308m in emergency funds for the two states hit by the flooding, along with food baskets, mattresses and blankets.
It has also pledged more funding along with a credit line of $560m for reconstruction.
On Thursday, Luiz Inacio Lula da Silva, the Brazilian president, travelled to the worst-hit areas to see the scale of the destruction for himself, pledging there would be "no limits" in helping the region to recover.
Lula also canceled his visit to Canada for the G20 summit to oversee the rescue effort.
Speaking to reporters he said none of the photos and videos he had seen showed "the gravity of the situation we saw when we took to the streets of these cities", adding that he would ensure rescue and recovery efforts received all that was needed.
"I want to tell you that there will be no limits and that we will overcome the usual bureaucracy that always gets in our way."
Alagoas state officials said it was difficult to calculate the losses caused by the floods, but an initial, conservative estimate put it at at least $450m.