Weeks of heavy rain in Brazil's usually drought-stricken north-east have left at least 14 people dead, civil defence officials have said.
Tens of thousands have been left homeless by the flooding and mudslides, the worst in more than 20 years.
Brazilian President Luiz Inacio Lula da Silva is due to visit some of the worst affected areas later in the day.
In Colombia, the rainy season has so far left 45 people dead, a Red Cross spokesman has told local media.
The worst-hit areas are in the Andean region and the south-west of the country, Red Cross director Carlos Ivan Marquez told Colombia's Caracol Radio.
Brazil's normally arid north-east has been battered by a month of rains.
The governor of one of the hardest-hit states, Piaui, has declared an emergency in 19 towns and cities and asked for military assistance to help those stranded by the flooding.
In the state of Maranhao, six people have been killed and two are missing, while several major roads have been flooded, civil defence officials say.
Torrential downpours have also caused rivers to break their banks in the Amazon region.
Forecasters say heavy rains are expected to continue in the north and north-east of Brazil until the middle of the month.