Some 40 hours of non-stop rain fell in the region
Chile has declared an emergency in southern areas where torrential rains have left at least eight people dead and caused widespread flooding.
Some 23,000 people have been affected by the rains, said to be the heaviest in more than 30 years.
Helicopters have been used to reach some residents, but in the worst-hit areas boats are needed for rescue work.
Officials say food, blankets and fuel are being sent to the area, although many roads have been cut off.
President Michelle Bachelet, who visited the area on Wednesday, asked people to be patient, saying aid work would initially focus on the most urgent cases.
"All the resources necessary will be used, just as in previous emergencies," she said.
The worst affected region is La Araucania, some 500km (300 miles) from the capital, Santiago.
"The situation is really tough. The overflowing of the rivers has left many people isolated. In many places, the helicopter was not able to land so they (the rescue crews) will have to get there by boat," said the regional governor, Nora Barrientos.
Officials quoted by the Associated Press said 40 hours of non-stop rain fell in the area around the town of Temuco, finally stopping on Tuesday morning.
The regions of Bio Bio and Los Rios have also seen flooding.